Question 6

Assume that a sample is used to estimate the mean tip earned by a serving staff at a diner. Find the margin of errorM.E. that corresponds to a sample of size 6 servers with a mean of $84.31 and a standard deviation of $6.22 at a confidence level of 99%.

Report ME accurate to one decimal place because the sample statistics are presented with this accuracy.

M.E. = $______

Question 7

In a survey, 19 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $44 and standard deviation of $9. Find the margin of error at a 98% confidence level.

Give your answer to two decimal places (cost/money is usually rounded 2 decimals).

$________

Question 9

Eloisa wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery.

She randomly selects a sample of 51 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 11.6 and a standard deviation of 2.3.

What is the 90% confidence interval for the number of chocolate chips per cookie for Big Chip cookies?

Enter your answers accurate to one decimal place (because the sample statistics are reported accurate to one decimal place).

With 90% confidence Eloisa estimates the true mean amount of chocolate chips is between_______ chocolate chips and______ chocolate chips per cookie.

Question 3

For a confidence level of 95% with a sample size of 11, find the criticalt value.

Question 5

The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 81.5 mmHg for a sample of size 357 and standard deviation 5.9 mmHg.

Note: Blood pressure is measured in units of millimeters of mercury (mmHg).

Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 98% confidence level).

Enter your answer accurate to one decimal place (because the sample statistics are reported accurate to one decimal place).

The sample estimates that the true mean reduction in systolic blood pressure____ mmHgand_____ mmHg with 98% confidence.

Answers should be obtained without any preliminary rounding.

Question 13

You intend to estimate the population mean time of finish times in a 5K (3.1 miles) road race from the following sample.

28.2	28.8	37	30.4
32.8	33.4	32.7	28.2
37.3	39.7	31.9	34.5
34.8	32.4	13.9	43.3
27.2	47.1	37.8	30.7
29.5	41.6	26.9	35.8
30.3	30.2	28.3	32.6
21	28.1	33.6	29.8
34.9	38.3	34.9	26.3
27.5	40.5	29.4	24.5
30.3	18.7	34.6	16.1
32	34.3	43.3	33.4
34.5	29.2	33.9	31.1
33.9	45.5	31.4	32.6
37.7	28.2	42.1	40
24.2	31.2

Find the 90% confidence interval. Enter your answer as a decimal accurate to two decimal place (because the sample data are reported accurate to one decimal place).

With 90% confidence the mean time of all runners in the 5K is between_______ minutes and_______ minutes.