Question 8

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 $14. Construct a confidence interval at a 98% confidence level. Write your interval in the form of point estimatemargin of error and give your answers to one decimal place. ________ ________

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 41 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 5.4 and a standard deviation of 3.8. What is the 99% 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 99% confidence Eloisa estimates the true mean amount of chocolate chips is between________ chocolatechips and_________ chocolatechips per cookie.

Question 10

A grocery store wishes to estimate the mean age of canned food in their store. They take a sample of 74 items and found a mean of 3.4 months with a standard deviation of 4.8 month. Find the 90% confidence interval for the age of the canned food items. Enter your answer accurate to one decimal place. With 90% confidence the sample estimates the mean age of canned food items to be between______ months and_______ months.

Question 11

Assume that a sample is used to estimate a population the mean hourly wage of employees working in a city's tourism industry (hotels, theme parks, transportation).

Find the 98% confidence interval given the statistical output below

Descriptive Statistics:

n = 741

x=$15.64

s = $3.66

Enter your answer accurate to two decimal place (because the sample statistics are reported accurate to one decimal place). With 98% confidence the sample estimate's the mean hourly wage of all tourism employees to be between_______$ per hour and_______ $ per hour.

Question 12

You intend to estimate a population mean with the following sample.

56.4

64.4

53.2

35.1

82.5

70.2

86.2

68.2

53.2

27.3

63.4

67.6

You believe the population is normally distributed. Find the 90% confidence interval. Enter your answer as an open-interval (i.e., parentheses) accurate to two decimal places (because the sample data are reported accurate to one decimal place). 90% C.I. = Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.