Today I spent 90 minutes playing sports. Sixty percent of the time I was playing tennis. For how many minutes did I play tennis?
2 answers:
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Answer:
0.0073 < 0.05, which means that we reject the null hypothesis and conclude that the true proportion of interest is higher than 0.7.
Step-by-step explanation:
Conduct a test to determine whether the true proportion of interest is higher than 0.7.
This means that the null hypothesis is:
And the alternate hypothesis is:
The test statistic is:
In which X is the sample mean, is the value tested at the null hypothesis,
is the standard deviation and n is the size of the sample.
0.7 is tested at the null hypothesis:
This means that
The sociologist found that 375 of the 500 travelers randomly selected and interviewed indicated that the airports were safe.
This means that
Value of the z-statistic:
P-value of the test:
Probability of z being larger than 2.44, that is, a proportion larger than 0.75.
This is, looking at the z-table, 1 subtracted by the pvalue of Z = 2.44. S
Z = 2.44 has a pvalue of 0.9927
1 - 0.9927 = 0.0073
0.0073 < 0.05, which means that we reject the null hypothesis and conclude that the true proportion of interest is higher than 0.7.