2 Sample T-test

A randomized double-blind test was done to test the effectiveness of a drug designed to prolong life in terminal cancer patients. 17 patients took the drug and 10 patients took the placebo. The survival time (in months) was recorded for each patient.

nMeanSDDrug173016Placebo10209

For a, b, c fill in each blank with either =, >, <, or .

a.H₀: _drug- _placebo

=

>

<

0

Tries 0/1b.Suppose you have prior evidence that the drug works then H_a: _drug- _placebo

=

>

<

0

Tries 0/1c.Suppose you have no idea if the drug works at the start of the study but after looking at the results you believe it does, then H_a: _drug- _placebo

=

>

<

0

Tries 0/1

d.What is the SE⁺_difference?

Tries 0/3

e.What is the t-statistic?

Tries 0/3

f.How many df?

Tries 0/3g.Use thet tableto determine the p-value for the 2-sided H_a.

< 5%

Between 5% and 10%

Between 10% and 20%

> 20%

Tries 0/1h.Would both the 1-sided and 2 sided alternatives reject the null at the 5% cut-off?

Yes

No, only the 1-sided one would.

No, only the 2-sided one would

Neither

Tries 0/1i.If you used the Z test would your p-values be bigger or smaller?

smaller

bigger