Sheila buys some boxes of pens with 20 pens in each box. Which expression represents the total number of pens Sheila bought?
2 answers:
You might be interested in
Answer:
The degrees of freedom are
And the p value is given by:
Since the p value for this cae is lower than the significance level of 0.05 we have enough evidence to reject the null hypothesis and we can conclude that the true means for this case are significantly different
Step-by-step explanation:
When we have two independent samples from two normal distributions with equal variances we are assuming that
And the statistic is given by this formula:
Where t follows a t distribution with degrees of freedom and the pooled variance
is given by this formula:
The system of hypothesis on this case are:
Null hypothesis:
Alternative hypothesis:
We have the following data given:
represent the sample size for group 1
represent the sample size for group 2
represent the sample mean for the group 1
represent the sample mean for the group 2
represent the sample standard deviation for group 1
represent the sample standard deviation for group 2
First we can begin finding the pooled variance:
And the deviation would be just the square root of the variance:
The statistic is givne by:
The degrees of freedom are
And the p value is given by:
Since the p value for this cae is lower than the significance level of 0.05 we have enough evidence to reject the null hypothesis and we can conclude that the true means for this case are significantly different