Answer:
Using Excel we can use the following code: "=2*T.DIST(-3.65;284;TRUE)"
So the p value is a very low value and using any significance level giveen always
so we can conclude that we have enough evidence to reject the null hypothesis, and there is enough evidence to conclude that the means are different.
Step-by-step explanation:
1) Data given and notation
represent the mean for the males
represent the mean for females
represent the sample standard deviation for males
represent the sample standard deviation for female
sample size for the group poisoned
sample size for the group unpoisoned
t would represent the statistic (variable of interest)
2) Concepts and formulas to use
We need to conduct a hypothesis in order to check if the mean for the two groups are equal or not , the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
If we analyze the size for the samples both are higher than 30 but the population deviations are not given, so for this case is better apply a t test to compare means, and the statistic is given by:
(1)
t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.
3) Calculate the statistic
We can replace in formula (1) the results obtained like this:
4) Statistical decision
The first step is calculate the degrees of freedom, on this case:
Since is a two tailed test the p value would be:
Using Excel we can use the following code: "=2*T.DIST(-3.65;284;TRUE)"
So the p value is a very low value and using any significance level giveen always
so we can conclude that we have enough evidence to reject the null hypothesis, and there is enough evidence to conclude that the means are different.