T-tests Flashcards
What is a t-test?
It’s a test to determine if there is statistically significant difference between
the means of two groups.
What are some good to know characteristics of t-tests?
- Usually with small sample size.
- Population standard deviation is unknown.
What are the different types of t-tests?
- One-sample t-test
- two-sample t-test
- paired t-test
What are the two parts of a one sample t-test?
mean vs given number
What are the two parts of a two sample t-test?
mean sample 1 vs mean sample 2
What are the two parts of a paired t-test?
mean of the same sample at two different times
What are the steps of conducting a t-test?
- State the null and the alternate hypotheses
- Compute the t value
- Figure out the critical value of t (use 5% level of significance)
- Make Statistical Decision
- Draw Managerial Conclusions
What are the steps of figuring out the critical value of t?
A. Level of significance (5%)
B. One-tail or two-tail
C. Find out the degree of
Freedom (df)
D. Find out the critical value of
t, given the degree of freedom
What is a one tail test?
A test that looks for an increase or decrease in the parameter and is down when the direction of the effect is known.
What is a two tail test?
The critical area of a distribution is two-sided and is used when you only want to test if there is a difference.
When is a the right tail test done?
When you want to test whether sample mean is significantly greater than a hypothesized mean.
When is a the left tail test done?
When you want to test whether sample mean is significantly less than a hypothesized mean
What is a significance level?
It is the probability that the event could have occurred by chance and is denoted by alpha
What excel function is used to compute the mean of a series of data?
=AVERAGE(Bi:Bj)
What excel function is used to compute the standard deviation of a series of data?
=STDEV.S(Bi:Bj)
