Business students taking statistics at Colonel Samuel College believe that the mean score on a first statistics test is at most 70. An instructor, intending to prove that the mean score is higher, randomly samples 18 statistics students and obtains the following scores:

63.9	62.7	88	73.5	96	73.5
83.2	64.3	74.4	83.2	74.4	73.5
66.5	85.5	83.2	66.5	62.7	68.4

Test grades are believed to be normally distributed. Use a significance level of 10%. Round answers to at least 3 decimal places.

A. Select the appropriate alternative hypothesis, H1orHa:H1orHa: =70=70

• 7070
• 7070
• >70>70
• 7070
• <70

1. Calculate the sample mean: _____
2. Calculate the estimated standard error of the sample mean: ______
3. Calculate the test statistic: t=
4. State the critical value at =0.1 =
5. Decision:
   • Fail to reject the null hypothesis

• Reject the null hypothesis.