Question

Determine which of the following studies would be tested with a t test for independent means.

​(a)	Upper A researcher measures work quality for 25 employees before and after taking an hourA researcher measures work quality for 25 employees before and after taking an hour break.break. nothing nothing nothing nothing nothing
​(b)	Upper A researcher measures satisfaction in 13 employees before and after receiving a raise.A researcher measures satisfaction in 13 employees before and after receiving a raise. nothing nothing nothing nothing nothing nothing
​(c)	Upper A researcher randomly assigns 22 athletes to drink a new energy drink and 25 athletesA researcher randomly assigns 22 athletes to drink a new energy drink and 25 athletes to drinkto drink water comma and then testswater, and then tests the endurance of eachthe endurance of each individual.individual. nothing nothing
​(d)	Upper A researcher randomly assigns a group of 22 employees to take a half hour break andA researcher randomly assigns a group of 22 employees to take a half hour break and 28 other28 other workers to take a 15 minuteworkers to take a 15 minute break comma and then testsbreak, and then tests how quickly theyhow quickly they can completecan complete a certain task.a certain task.

Answer 1

a)we use paired t test ( dependent sample t test) because use the sampel sample before and after.

Ans : paired t test

b) this is also a paired t test , we have tested the same employees before and after the raise.

Ans : paired t test

C) uses t test for independent means.The t test for independent means is used when we want to know whether there is a difference between populations.

ans: t independent samples .

d) ans : t test for independent samples.

Since the sample size is small and samples are independent.