Question

You took a random sample of 12 two-slice toasters and found the mean price was $61.12 and the standard deviation was $24.62. Construct a 95% confidence interval for the population mean. Assume the prices are normally distributed.

Answer 1

Answer:

Step-by-step explanation:

We want to determine a 95% confidence interval for the population mean for the prices of slice toasters.

Number of sample, n = 12

Mean, u = $61.12

Standard deviation, s = $24.62

For a confidence level of 95%, the corresponding z value is 1.96.

We will apply the formula

Confidence interval

= mean ± z ×standard deviation/√n

It becomes

61.12 ± 1.96 × 24.62/√12

= 61.12 ± 1.96 × 7.107

= 61.12 ± 13.93

The lower end of the confidence interval is 61.12 - 13.93 =47.19

The upper end of the confidence interval is 61.12 + 13.93 = 75.05