A random sample of 100 observations from a normal population ...

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A random sample of 100 observations from a normal population whose standard deviation is 50 produced a mean of 75 . Does this statistic provide sufficient evidence at the 5 level of significance to infer that the population mean is not 80?

Question 2

A nonparametric method that is equivalent to the Wilcoxon rank sum test is the:
 a. Wilcoxon signed rank sum test. c. Kruskal-Wallis test.
  b. Friedman test. d. Mann-Whitney test.

[Missbam101]

Answer to Question 1

H0:  = 80 vs. H1:   80
Rejection region:  z  > z.025 = 1.96
Test statistic: z = -1.0
Conclusion: Don't reject H0 . Insufficient evidence at the 5 level to say the population mean differs from 80.

Answer to Question 2

D

[cool]

Excellent

[jamesnevil303]

Gracias!