Which of the following is not true about the student's t distribution? a. it has more area in the tails and less in the center than does the normal distribution. b. it is used to construct confidence intervals for the population mean when the population standard deviation is known. c. it is bell shaped and symmetrical. d. as the number of degrees of freedom increases, the t distribution approaches the normal distribution. e. both (a) and (b)

b. It is used to construct confidence intervals for the population mean when the population standard deviation is known

Step-by-step explanation:

Student's t-distribution, also called sometimes just as t distribution,  is a probability distribution that is used to estimate population parameters when you have small sample size, specifically when sample size is less than 30, or when the population standard deviation is unknown.

The t distribution allows us to conduct statistical analyses on samples that does not satisfy the conditions for applying standard normal distribution.

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls

6/20

step-by-step explanation: