STA1003 Weekly Revision PDF

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WEEKLY REVISION Week 1. Populations and Samples_1. Revision 1. Q.1.An Australian consumer organisation has received many complaints about the "Do_it_all" dishwasher. They would like to know what proportion of people who have purchased this dishwasher in the last 12 months are unhappy with the product. They obtain a list of all 3423 people who have purchased the dishwasher in the last 12 months and randomly select 100 purchasers. They contact each of these people and ask them if they have had any problems with the dishwasher. What is the population the consumer organisation is interested in?    

All people who have purchased the "Do_it_all" dishwasher in the last 12 months All 100 people contacted by the consumer organisation All owners of dishwashers All people who are unhappy with their "Do_it_all " dishwasher

Q.2. An Australian consumer organisation has received many complaints about the "Do_it_all" dishwasher. They would like to know what proportion of people who have purchased this dishwasher in the last 12 months are unhappy with the product. They obtain a list of all 3423 people who have purchased the dishwasher in the last 12 months and randomly select 100 purchasers. They contact each of these people and ask them if they have had any problems with the dishwasher. What is the population the sample was taken from?    

All people who have purchased the "Do_it_all " dishwasher in the last 12 months All 100 people contacted by the consumer organisation All owners of dishwashers All people who are unhappy with the "Do_it_all" dishwasher

Q.3. What is the size of the sample in this study? 100.0 Q.4.The administration of "Knowitall University" want to know what proportion of their students are satisfied with the library facilities. The library staff are keen to help. They select 200 students in the library during the first week of the exam period and ask them to fill in a questionnaire on satisfaction with the library. What is the population that the sample was selected from?    

All students enrolled at "Knowitall University" All 200 students who completed the questionnaire All university students All students in the library during the first week of the exam period

Q.5.In the survey conducted by the library staff at "Knowitall University", what is the population the university administration is interested in?    

All students enrolled at "Knowitall University" All students in the library during the first week of the exam period All university students All 200 students who completed the questionnaire

Q.6.How many students were in the sample selected by library staff? 200.0

Revision quiz 2.

Q1. The "Easy Link" Internet provider is thinking of giving their long term customers a 'reward' as part of a promotional campaign. In order to know how much the scheme would cost, they need to know what proportion of their current customers have been with them for more than 5 years. Their records are rather disorganised and it takes a long time to find the length of time a customer has been with the company, so they don't want to have to search the records of all 12,304 current customers. From their customer records, they randomly select 100 customers, and check the length of time these customers have been with the company. What is the population "Easy Link" is interested in?    

All current customers of "Easy Link" All users of the Internet All 100 customers who were surveyed All long term customers of "Easy Link"

Q2. The "Easy Link" Internet provider is thinking of giving their long term customers a 'reward' as part of a promotional campaign. In order to know how much the scheme would cost, they need to know what proportion of their current customers have been with them for more than 5 years. Their records are rather disorganised and it takes a long time to find the length of time a customer has been with the company, so they don't want to have to search the records of all 12,304 current customers. From their customer records, they randomly select 100 customers, and check the length of time these customers have been with the company. What is the population the sample was chosen from?    

All current customers of "Easy Link" All users of the Internet All 100 customers who were surveyed All long term customers of "Easy Link"

Q3. Whati st hesi z eoft hes ampl e?100. 0 Q4.Al oc al r adi ost at i on( 3DUM)wantt oknowwhatpr opor t i onoft hei raudi enceenj oy l i st eni ngt o' t al kback' pr ogr ams .Dur i ngt hepopul ar' Tel li tt oDan' t al kbackpr ogr am on Tuesdaymor ni ngs ,t heyas kl i st ener st ocal l i nandsaywhet hert heyenj oyl i st eni ngt ot al k back .Fi f t yl i st ener scal l i nwi t ht hei ropi ni on. Whati st hepopul at i ont her adi ost at i oni si nt er es t edi n?    

All 3DUM listeners All 50 people who called in All people listening to the 'Tell it to Dan' program All people who like talk back radio

Q5. A local radio station (3DUM) want to know what proportion of their audience enjoy listening to 'talk back' programs. During the popular 'Tell it to Dan' talk back program on Tuesday mornings, they ask listeners to call in and say whether they enjoy listening to talk back. Fifty listeners call in with their opinion. What is the population the sample was chosen from?    

All 3DUM listeners All 50 people who called in All people listening to the 'Tell it to Dan' program All people who like talk back radio

Q6. A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They employ someone who approaches 200 people at the fair to ask them whether the amount of money the council spends on the fair is appropriate. What is the population the local council is interested in?    

All local residents All people who attend the fair All 200 people who are approached at the fair All local residents who attend the fair

Q7.A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They employ someone who approaches 200 people at the fair to ask them whether the amount of money the council spends on the fair is appropriate. What is the population the sample was selected from?    

All local residents All people who attend the fair All 200 people who are approached at the fair All local residents who attend the fair

Populations and Samples_2. Percentages and proportions Q1. The "Easy Link" Internet provider is thinking of giving their long term customers a 'reward' as part of a promotional campaign. In order to know how much the scheme would cost, they need to know what proportion of their current customers have been with them for more than 5 years. Their records are rather disorganised and it takes a long time to find the length of time a customer has been with the company, so they don't want to have to search the records of all 12,304 current customers. From their customer records, they randomly select 100 customers, and check the length of time these customers have been with the company. What is the population "Easy Link" is interested in?    

All current customers of "Easy Link" All users of the Internet All 100 customers who were surveyed All long term customers of "Easy Link"

Q2. The "Easy Link" Internet provider is thinking of giving their long term customers a 'reward' as part of a promotional campaign. In order to know how much the scheme would cost, they need to know what proportion of their current customers have been with them for more than 5 years. Their records are rather disorganised and it takes a long time to find the length of time a customer has been with the company, so they don't want to have to search the records of all 12,304 current customers. From their customer records, they randomly select 100 customers, and check the length of time these customers have been with the company. What is the population the sample was chosen from?    

All current customers of "Easy Link" All users of the Internet All 100 customers who were surveyed All long term customers of "Easy Link"

Q3. What is the size of the sample? 100.0 Q4. A local radio station (3DUM) want to know what proportion of their audience enjoy listening to 'talk back' programs. During the popular 'Tell it to Dan' talk back program on Tuesday mornings, they ask listeners to call in and say whether they enjoy listening to talk back. Fifty listeners call in with their opinion.

What is the population the radio station is interested in?    

All 3DUM listeners All 50 people who called in All people listening to the 'Tell it to Dan' program All people who like talk back radio

Q5. A local radio station (3DUM) want to know what proportion of their audience enjoy listening to 'talk back' programs. During the popular 'Tell it to Dan' talk back program on Tuesday mornings, they ask listeners to call in and say whether they enjoy listening to talk back. Fifty listeners call in with their opinion. What is the population the sample was chosen from?    

All 3DUM listeners All 50 people who called in All people listening to the 'Tell it to Dan' program All people who like talk back radio

Q6.A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They employ someone who approaches 200 people at the fair to ask them whether the amount of money the council spends on the fair is appropriate. What is the population the local council is interested in?    

All local residents All people who attend the fair All 200 people who are approached at the fair All local residents who attend the fair

Q7. A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They employ someone who approaches 200 people at the fair to ask them whether the amount of money the council spends on the fair is appropriate. What is the population the sample was selected from?    

All local residents All people who attend the fair All 200 people who are approached at the fair All local residents who attend the fair

Calculating Percentages Q1. In a sample of 850 computer technicians, 472 play chess. Calculate the sample percentage. Give your answer correct to one (1) decimal places - Do NOT include the % sign. eg 12.3 A.55.5 Q2. In a sample of 760 primary school children, 298 play a musical instrument. Calculate the sample percentage. Give your answer correct to one (1) decimal places - Do NOT include the % sign. eg 12.3 A.39.2

Q3. In a sample of 500 theatre patrons, 139 bought ice-creams.

Calculate the sample percentage. Give your answer correct to one (1) decimal places - Do NOT include the % sign. eg 12.3 A. 27.8 Q4. In a sample of 1920 cruise passengers, 399 reported being seasick. Calculate the sample percentage. Give your answer correct to one (1) decimal places - Do NOT include the % sign. eg 12.3 A.20.8 Calculating Proportions Q1. In a sample of 210 pet owners, only 20 owned parrots. A. .095 OR 0.095 Calculate the sample proportion. Give your answer correct to three (3) decimal places. eg .123 Q2.In a sample of 210 pet owners, only 20 owned parrots. Calculate the sample proportion. Give your answer correct to three (3) decimal places. eg .123 A. .835 OR 0.835 Q3. In a sample of 850 computer technicians, 470 play chess. Calculate the sample proportion. Give your answer correct to three (3) decimal places. eg .123 A. 553 OR 0.553 Q4. In a sample of 2030 academics, 577 wear glasses. Q5. Calculate the sample proportion. Give your answer correct to three (3) decimal places. eg .123 A. 0.284 Q6. In a sample of 170 pensioners, 68 liked to play Bingo. Calculate the sample proportion. Give your answer correct to three (3) decimal places. eg .123 A.0400 Detecting bias [Topic 1.2] Q1. An Australian consumer organisation has received many complaints about the "Do_it_all" dishwasher. They would like to know what proportion of people who have purchased this dishwasher in the last 12 months are unhappy with the product. They obtain a list of all 3423 people who have purchased the dishwasher in the last 12 months and randomly select 100 purchasers. They contact each of these people and ask them if they have had any problems with the dishwasher. If we wanted to draw conclusions about all people who purchased a "Do_it_all" dishwasher in the past 12 months, was the sample selection biased or unbiased?  

biased unbiased

Q2.The administration of "Knowitall University" want to know what proportion of their students are satisfied with the library facilities. The library staff are keen to help. During the first week of the exam period they choose 200 students who are in the library and ask them to fill in a questionnaire on satisfaction with the library.

If we wanted to draw conclusions about all students at "Knowitall University", the sample selection was  

Probably biased Probably unbiased

Q3. The administration of "Knowitall University" want to know what proportion of their students are satisfied with the library facilities. The library staff are keen to help. During the first week of the exam period they choose 200 students who are in the library and ask them to fill in a questionnaire on satisfaction with the library. If we wanted to draw conclusions about all students who used the library in the first week of the exam period, the sample selection was  

Probably biased Probably unbiased

Q4.A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They randomly select 200 local residents and ask them "Do you agree that the council wastes far too much of the rate payers money on the annual Town Fair?" If we want to draw conclusions about the attitude of local residents to council expenditure on the Town Fair, this study is  

Probably biased, because the sample selection was biased. Probably biased because the question was biased.

Q1.A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They employ someone who approaches 200 people at the fair to ask them "Do you think the amount of money the council spends on the Town Fair is reasonable, or is the council spending too much?". If the council wish to draw a conclusion about all local residents, this study was    

Probably biased, because the sample selection was biased. Probably biased because the question was biased. Probably biased because the question was biased and the sample selection was biased. Probably unbiased.

Q2. A local radio station (3DUM) want to know what proportion of their audience enjoy listening to 'talk back' programs. During the popular 'Tell it to Dan' talk back program on Tuesday mornings, they ask listeners to call in and say if they enjoy listening to talk back. Of the 50 listeners call in 47 say they enjoy talk back radio. If the radio station is interested in all of its audience, the information from this study is    

Probably biased, because the sample selection was biased. Probably biased because the question was biased. Probably unbiased Probably biased because the question was biased and the sample selection was biased.

Q3. The "Easy Link" Internet provider is thinking of giving their long term customers a 'reward' as part of a promotional campaign. In order to know how much the scheme would cost, they need to know what proportion of their current customers have been with them for more than 5 years. Their records are rather disorganised and it takes a long time to find the length of time a customer has been with the company, so they don't want to have to search the records of all 12,304 current customers. From their customer records, they randomly select 100 customers, and check the length of time these customers have been with the company. If "Easy Link" want to draw conclusions about all of their customers, the sample selection is

 

Probably unbiased Probably biased.

Q4.A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They employ someone who approaches 200 people at the fair to ask them "Do you agree that the council spends far too much money on the annual Town Fair?". If the council wish to draw a conclusion about all local residents, this study was    

Probably biased, because the sample selection was biased. Probably biased because the question was biased. Probably biased because the question was biased and the sample selection was biased. Probably unbiased.

Impact of bias Q1. An Australian consumer organisation has received many complaints about the "Do_it_all" dishwasher. They would like to know what proportion of people who have purchased this dishwasher in the last 12 months are unhappy with the product. They obtain a list of all 3423 people who have purchased the dishwasher in the last 12 months and randomly select 100 purchasers. They contact each of these people and ask them if they have had any problems with the dishwasher. 40 of the consumers report that they have had problems with the dishwasher What could we conclude about the proportion of "Do_it_all" dishwasher purchasers who have experienced problems with the product?   

We can't tell exactly what percentage of people who have purchased the dishwasher over the past 12 months have experienced problems with the product, but the percentage is probably somewhere around 40%. We can't draw any conclusions about what percentage of people who have purchased the dishwasher over the past 12 months have experienced problems with the product. 40% of all people who have purchased the dishwasher over the past 12 months have experienced problems with the product.

Q2.The administration of "Knowitall University" want to know what proportion of their students are satisfied with the library facilities. The library staff are keen to help. They select 200 students in the library during the first week of the exam period and ask them to fill in a questionnaire on satisfaction with the library. Of the 200 students 79% were satisfied with the library facilities. From this study we can conclude that   

We can't draw any conclusions about the percentage of students at "Knowitall University" who are satisfied with the library facilities. We can't tell exactly what percentage of students at "Knowitall University" are satisfied with the library facilities, but it is probably somewhere around 79%. 79% of students at "Knowitall University" are satisfied with the library facilities.

Q3. A local council want to know what proportion of their residents are satisfied with the money spent on the annual Town Fair. They randomly select 200 local residents and ask them "Do you agree that the council wastes far too much of the rate payers money on the annual Town Fair?" 65% of respondents agree that the council is spending too much money on the fair.

What conclusion can we draw about the percentage of local residents who think the council spends too much on the fair?  

We can't draw any conclusions about what percentage of local residents think the council spends too much on the fair. 65% of local residents think the council spends too much on the fair.



We can't tell exactly what percentage of local residents think the council spends too much on the fair, but it is probably somewhere around 65%.

Ev eni ft hes ampl esel ec t i oni sbi asedwecanst i l l dr awsomeconcl us i onsaboutt he popul at i onofi nt er es t .  

True False

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