Question

the prices in dollars for a particular phone are shown below for 7 online retailers. estimate and interpret the true mean price for this particular phone with 95% confidence.

1015   1022   977   1000   985   950   998

Answer 1

From the sample data,

Sample mean = 992.4286

Sample standard deviation = S = 24.3780

t critical value at 0.05 level with 6 df = 2.447

95% Confidence interval for is

- t * S / sqrt(n) < < + t * S / sqrt(n)

992.4286 - 2.447 * 24.3780 / sqrt(7) < < 992.4286 + 2.447 * 24.3780 / sqrt(7)

969.88 < < 1014.98

95% CI is ( 969.88 , 1014.98 )