1-) A quality control department noted took a sample of 40 product, and found the mean number of defect to be 6.15, with a standard deviation of 2.53 . The distribution was known to be normal. Construct a 95 percent confidence interval for the mean number of defects
2-) A corporation is trying to estimate the mean amount an employee's spends on dental care. They survey 45 employees, and find a mean amount spent of $1820, with a sample std dev of $660. Find a 95% confidence interval for the mean amount spent
3-) Pepsi wants to estimate an average number of cans of Pepsi consumed. The sample 16 people and find the mean number of cans to be 60 with a sample standard deviation of cans of 20
a. Is the t or z distribution used here? Why?
b. What is the value of the test statistic to be used for a 90% confidence interval?
c. Create a 90% confidence interval.
d. Could Pepsi be reasonable in concluding that the population mean is 59 cans?
4-) Last year a survey showed that 30% of travelers stay in budget hotels. The hotel association wants to update this proportion. .
a. The new study is to use the 90 percent confidence level. The estimate is to be within 1 percent of the population proportion. What is the necessary sample size?
b. If we wanted to reduce the required sample size, what could we do?
5-) A survey of singles was made regarding their restaurant eating habits. A sample of 60 singles had a sample mean number of restaurant visits was 2.76 meals per week. The std deviation of the sample was 0.75 meals per week. Create a 98 percent confidence interval for the mean of the population.