A group of 59 randomly selected students have a mean score of 29.5 with a standard

deviation of 5.2 on a placement test. What is the 90% confidence interval for the mean

score, ", of all students taking the test?

And we can conclude that the true mean for the scores are given by this interval (28.37; 30.63) at 90% of confidence

Step-by-step explanation:

Information given

represent the sample mean

population mean  

s= 5.2 represent the sample standard deviation

n=59 represent the sample size  

Confidence interval

The confidence interval for the true mean is given by the following formula:

  (1)

The degrees of freedom are given by:

The Confidence interval is 0.90 or 90%, the significance is and , and the critical value is

Now we have everything in order to replace into formula (1):

And we can conclude that the true mean for the scores are given by this interval (28.37; 30.63) at 90% of confidence

me

step-by-step explanation:

there is no grid

step-by-step explanation: