Question

1.) Justin is interested in buying a digital phone. He visited 15 stores at random and recorded the price of the particular phone he wants. The sample of prices had a mean of 237.64 and a standard deviation of 8.63.

(a) What t-score should be used for a 95% confidence interval for the mean, μ, of the distribution?
t* = _____________

(b) Calculate a 95% confidence interval for the mean price of this model of digital phone:
(Enter the smaller value in the left answer box.)

_________ to __________

2.) Test the claim that for the population of statistics final exams, the mean score is 71 using alternative hypothesis that the mean score is different from 71. Sample statistics include n=18, x¯=73, and s=12 Use a significance level of α=0.05. (Assume normally distributed population.)
The test statistic is ____________
The positive critical value is _____________
The negative critical value is _____________
The conclusion is ___________

Answer 1