Question

A survey of 25 grocery stores revealed that the mean price of a gallon of milk was $2.98, with a standard error of $0.10. If 90% and 95% confidence intervals were developed to estimate the true cost of a gallon of milk, what similarities would they have?
A. Both use the same t statistic
B. Both have the same confidence level
C. Both use the same z statisticD. Both use the same point estimate of the population mean

Answer 1

Answer:

Option D) Both use the same point estimate of the population mean      

Step-by-step explanation:

We are given the following in the question:

Population mean, μ = $2.98

Standard error = $0.10

Sample size, n = 25

Confidence interval:  

$\bar{x} \pm t_{critical}(\text{Standard Error})$

90% and 95% confidence intervals

• The confidence level is not same.
• Since the confidence level are not same they cannot have the same z statistic or t statistic.

Thus, the correct answer is:

Option D) Both use the same point estimate of the population mean