Confidence Intervals for the Mean
t Distribution
Questions
Question 1 out of 5.
Select all of the following that are correct descriptions of the t distribution.
There are more scores in the tails than in a normal distribution. There are more scores in the center than in a normal distribution.
It is leptokurtic.
You use it when you do not know the population standard deviation.
A t distribution with 20 degrees of freedom has 95% of its distribution within 1.96 standard deviations of its mean.
Question 2 out of 5.
A t distribution with which of the following degrees of freedom is the closest to a normal distribution? 0
2
12
50
Question 3 out of 5.
For a t distribution with 15 degrees of freedom, 90% of the distribution is within how many standard deviations of the mean?
Question 4 out of 5.
In a t distribution with 10 degrees of freedom, what is the probability
of getting a value within two standard deviations of the mean?
Question 5 out of 5.
There is a population of test scores with an unknown standard
deviation. You sample 21 scores from this population, and you calculate
the mean and standard deviation. You get a value for the mean that is
1.5 standard errors greater than what you think is the population mean.
What is the probability that you would get a value 1.5 standard
deviations or more from the mean in this t distribution?