A random sample of 64 observations produced a mean value of 86 and standard deviation of 4.5. The 95% confidence interval for the population mean μ is between:.

(84.876, 87.124)

Step-by-step explanation:

Confidence interval for population mean if population standard deviation is unknown:

, where n= sample size

s= sample standard deviation

= sample mean

significance level

= critical-t value

Given:  n= 64

Degree of freedom = n-1 = 63

s= 4.5

= 86

0.05

= 1.9983

Now, the required 95% confidence interval would be:

The 95% confidence interval for the population mean μ is between: (84.876, 87.124)

the median here is 25. your lowest value is 14 and highest value is 48. to find the third quartile, find the medium number in between 25 and 48 which would be 42 i believe.