Question 1

Emma wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery. She randomly selects a sample of 68 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 15.5 and a standard deviation of 2.4. What is the 99% confidence interval for the number of chocolate chips per cookie for Big Chip cookies? Assume the data is from a normally distributed population.Round answers to 3 decimal places where possible. < <

Question 2

If n = 28,xx= 43, and s = 8, construct a confidence interval at a 99% confidence level. Assume the data came from a normally distributed population. Give your answers to three decimal places. <<

Question 3

Assume that a sample is used to estimate a population mean. Find the 80% confidence interval for a sample of size 326 with a mean of 67.2 and a standard deviation of 13.9. Enter your answer as a tri-linear inequality accurate to 3 decimal places. <<

Question 4

A botanist wishes to estimate the typical number of seeds for a certain fruit. She samples 75 specimens and counts the number of seeds in each. Use her sample results (mean = 62.6, standard deviation = 11.1) to find the 98% confidence interval for the number of seeds for the species. Enter your answer as anopen-interval(i.e., parentheses) accurate to 3 decimal places. 98% C.I. =???

Question 5

You measure 28 dogs' weights, and find they have a mean weight of 56 ounces. Assume the population standard deviation is 4.2 ounces. Based on this, what is the maximal margin of error associated with a 95% confidence interval for the true population mean dog weight. Give your answer as a decimal, to two places ounces

Question 6

In a survey, 12 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $37.3 and standard deviation of $18.6. Estimate how much a typical parent would spend on their child's birthday gift (use a 90% confidence level). Give your answers to 3 decimal places. Express your answer in the format ofxE. $ $

Question 7

A fitness center is interested in finding a 98% confidence interval for the mean number of days per week that Americans who are members of a fitness club go to their fitness center. Records of 256 members were looked at and their mean number of visits per week was 3.1 and the standard deviation was 1.6.

a. To compute the confidence interval use a ? t z distribution.

b. With98% confidence the population mean number of visits per week is between and visits.

c.If many groups of 256 randomly selected members are studied, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of visits per week and about percent will not contain the true population mean number of visits per week.

Question 8

A fitness center is interested in finding a 98% confidence interval for the mean number of days per week that Americans who are members of a fitness club go to their fitness center. Records of 218 members were looked at and their mean number of visits per week was 3.3 and the standard deviation was 2.8. Round answers to 3 decimal places where possible.

a. To compute the confidence interval use a ? z t distribution.

b. With98% confidence the population mean number of visits per week is between and visits.

c.If many groups of 218 randomly selected members are studied, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of visits per week and about percent will not contain the true population mean number of visits per week.

Question 9

A researcher is interested in finding a 98% confidence interval for the mean number minutes students are concentrating on their professor during a one hour statistics lecture. The study included 129 students who averaged 41.9 minutes concentrating on their professor during the hour lecture. The standard deviation was 11.7 minutes.

a. To compute the confidence interval use a ? t z distribution.

b. With 98% confidence the population mean minutes of concentration is between(round to 3 decimal places) and minutes.

c.If many groups of 129 randomly selected members are studied, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean minutes of concentration and about percent will not contain the true population mean minutes of concentration.

Question 10

The high temperatures (in degrees Fahrenheit) of a random sample of 9 small towns are:

99.7

98

97.8

99.4

97.6

98.9

96.4

98.1

99.8

Assume high temperatures are normally distributed. Based on this data, find the 95% confidence interval of the mean high temperature of towns. Enter your answer as anopen-interval(i.e., parentheses) accurate to two decimal places (because the sample data are reported accurate to one decimal place). 95% C.I. =$$ Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.

Question 11

The body temperatures in degrees Fahrenheit of a sample of adults in one small town are:

96.7

96.8

98.2

96.3

98.6

97

97.2

99

97.4

96.5

98.9

99.4

97.3

Assume body temperatures of adults are normally distributed. Based on this data, find the 90% confidence interval of the mean body temperature of adults in the town. Enter your answer as anopen-interval(i.e., parentheses) accurate to 3 decimal places.Assume the data is from a normally distributed population. 90% C.I. =$$

Question 12

You are interested in finding a 98% confidence interval for the average commute that non-residential students have to their college. The data below show the number of commute miles for 11 randomly selected non-residential college students. Round answers to 3 decimal places where possible.

16

24

13

13

21

13

14

19

27

19

20

a. To compute the confidence interval use a ? z t distribution.

b. With98% confidence the population mean commute for non-residential college students is between and miles.

c.If many groups of 11 randomly selected non-residential college students are surveyed, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of commute miles and about percent will not contain the true population mean number of commute miles.

Question 13

You are interested in finding a 90% confidence interval for the average number of days of class that college students miss each year. The data below show the number of missed days for 10 randomly selected college students.Round answers to 3 decimal places where possible.

9

1

10

7

9

11

12

4

0

11

a. To compute the confidence interval use a ? t z distribution.

b. With90% confidence the population mean number of days of class that college students miss is between and days.

c.If many groups of 10 randomly selected non-residential college students are surveyed, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of missed class days and about percent will not contain the true population mean number of missed class days.

Question 14

You are interested in finding a 98% confidence interval for the average commute that non-residential students have to their college. The data below show the number of commute miles for 12 randomly selected non-residential college students.

14

24

23

25

24

26

11

28

22

17

21

25

a. To compute the confidence interval use a ? z t distribution.

b. With98% confidence the population mean commute for non-residential college students is between and miles.

c.If many groups of 12 randomly selected non-residential college students are surveyed, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of commute miles and about percent will not contain the true population mean number of commute miles.