In: Statistics and Probability
: A researcher is interested in whether salaries for middle school teachers were less than salaries for nurses in Arkansas. A statewide salary survey is conducted using random sampling.
The Data Analysis output for the various tests used when comparing two group means are shown below. The significance level was .05.
F-Test Two-Sample for Variances |
||
Teachers |
Nurses |
|
Mean |
45946.07 |
53365.13 |
Variance |
68256753 |
86820446 |
Observations |
300 |
300 |
df |
299 |
299 |
F |
0.7862 |
|
P(F<=f) one-tail |
0.0190 |
|
F Critical one-tail |
0.8265 |
t-Test: Paired Two Sample for Means |
||
Variable 1 |
Variable 2 |
|
Mean |
45946.07 |
53365.13 |
Variance |
68256753 |
86820446 |
Observations |
300 |
300 |
Pearson Correlation |
0.191488 |
|
Hypothesized Mean Difference |
0 |
|
df |
299 |
|
t Stat |
-11.4663 |
|
P(T<=t) one-tail |
9.01E-26 |
|
t Critical one-tail |
1.649966 |
|
P(T<=t) two-tail |
1.8E-25 |
|
t Critical two-tail |
1.96793 |
t-Test: Two-Sample Assuming Equal Variances |
||
Teachers |
Nurses |
|
Mean |
45946.07 |
53365.13 |
Variance |
68256753 |
86820446 |
Observations |
300 |
300 |
Pooled Variance |
77538599 |
|
Hypothesized Mean Difference |
0 |
|
df |
598 |
|
t Stat |
-10.319 |
|
P(T<=t) one-tail |
2.19E-23 |
|
t Critical one-tail |
1.647406 |
|
P(T<=t) two-tail |
4.37E-23 |
|
t Critical two-tail |
1.963939 |
t-Test: Two-Sample Assuming Unequal Variances |
||
Teachers |
Nurses |
|
Mean |
45946.07 |
53365.13 |
Variance |
68256753 |
86820446 |
Observations |
300 |
300 |
Hypothesized Mean Difference |
0 |
|
df |
590 |
|
t Stat |
-10.319 |
|
P(T<=t) one-tail |
2.3E-23 |
|
t Critical one-tail |
1.64744 |
|
P(T<=t) two-tail |
4.61E-23 |
|
t Critical two-tail |
1.963993 |
a) What is the appropriate two sample test to perform – the paired t test, the t test assuming equal variances, or the t test assuming unequal variances – for this research project?
b) State the H0 and Ha.
c) Identify the decision rule using the critical value of t (round to three decimal places).
d) Identify the decision rule using the p value method.
e) State the test statistic (t calc).
f) Do you reject or not reject Ho? Explain your decision.