MySpace
18
18
20
30
35
118
119
123
149
160
167
200
200
200
208
209
300
300
306
400
400
500
546

# MS 150 Statistics quiz nine • Name:

The table is the number of friends reported by MySpace users.

1. _____________ Calculate the sample size n.
2. _____________ Calculate the sample mean x.
3. _____________ Calculate the sample standard deviation sx.
4. _____________ Based on the data, what is the point estimate for the population mean μ?
5. _____________ Calculate the standard error SE of the mean.
6. _____________ Calculate the degrees of freedom n − 1.
7. _____________ Calculate t-critical tc for a confidence level of 95%.
8. _____________ Calculate the margin of error E for the mean.
9. p(__________ ≤ μ ≤ __________) = 0.95 Calculate the 95% confidence interval for the population mean.
10. _____________ FaceBook reports that the average number of friends is 130. Write out the null hypothesis that the population mean μ is 130 friends:
H0:
11. Write out the alternate hypothesis that the population mean μ is NOT 130 friends:
H1:

Run a hypothesis test at a risk of a type I error alpha α = 0.05
12. _____________ Calculate the value of the t-statistic t
13. _________________________________ Do we reject or fail to reject the null hypothesis?
14. _____________ Is the MySpace sample mean x statistically significantly different from the FaceBook population mean μ of 130 friends?