Question

Gillette claims that their double-edge shaver is better than the leading brand of single-edge shavers (Lady Bic). In a recent study, 26 women rated the Gillette and the Lady Bic shavers on smoothness, closeness and safety. One group of women were used and each woman recorded two scores. The mean difference of those scores were tested with the following results.

Critical Value…………… t = 1.645

Test statistic ..................... t = 1.978

P-value.............................. = . 031

Significance level ……........... = .05

Which number from the computer output is compared to the significance level     

                  to check if the null hypothesis should be rejected?

                  a) degrees of freedom    b)   test statistic      c) P-value         d) critical value

Answer 1

Given that,

The mean difference of those scores were tested with the following results.

Critical Value = tcrit= 1.645

Test statistic = t = 1.978

P-value = . 031

Significance level = .05

Decision Rule : Reject H0, if p-value is less than significance level.

Therefore, p-value is compared to the significance level to check if the null hypothesis should be rejected or not.

Here, p-value = 0.031 is less than significance level = 0.05, so we should reject the null hypothesis.

Answer : c) p-value