Question

a.            State the null hypothesis.

b.            Identify the appropriate statistical test

c.            Calculate the appropriate test statistic. Make sure to report the degrees of freedom for the statistical test (if appropriate). You must show your work to receive full credit.

d.            State your conclusions (use a two-tailed test with a = .05 for all tests).

e.            Compute an effect size.

A researcher knows that the weights of 6 year olds are normally distributed with m = 20 kg and s = 5.0. She suspects that children in poverty-stricken regions differ from the population. With a sample of n = 25 children, the researcher obtains a mean of 17 kg.

Answer 1

Given:

= 20, n = 25, = 17, SD(S) = 5, = 0.05

a)

Hypothesis:

Ho: = 20

Ha: 20

b) One sample t test

C)

Test statistic:

Degree of freedom = n-1 = 25-1 = 24

P-value = 0.0062                 ...................Using t table

d)

Conclusion:

P-value < α, i.e. 0.0062 < 0.05, That is Reject Ho at 5% level of significance.

e)

effect size = d =