Question

You hypothesize that drinking tea reduces stress levels so you design a study comparing stress levels between people who drink tea and people who do not drink tea. You collect data on 37 people and find that in your sample there are 20 people who do not drink tea and 17 people who drink tea. The mean stress score for non-tea drinkers is 84 with a standard deviation of 10, while the mean score for those who drink tea is 82 with a standard deviation of 11. Calculate the t-statistic. Round to the nearest tenth. Enter the absolute value of your answer (I.e., do not include a negative sign if the answer is negative).

Answer 1

The t-statistic is approximately -0.523.

Step-by-step explanation:

To calculate the t-statistic, we can use the formula:

t = (mean1 - mean2) / sqrt((sd1^2/n1) + (sd2^2/n2))

where mean1 and mean2 are the means of the two groups, sd1 and sd2 are the standard deviations of the two groups, and n1 and n2 are the sample sizes of the two groups.

Plugging in the values from the question:

t = (82 - 84) / sqrt((11^2/17) + (10^2/20))

t = -2 / sqrt((121/17) + (100/20))

t ≈ -0.523

The absolute value of the t-statistic is 0.523.