Question

1. Imagine that the psychology department wants to consult you on a project designed to measure how students’ expectations for the difficulty of Intro to Psychology class actually influences their final grade. The department randomly selects 50 Intro students at the beginning of the semester and asks them, “What grade do you expect to get in Intro to Psychology this semester?” Below are the numbers students reported for their expected grade.

Note: A = 4.0, B = 3.0, C = 2.0, D = 1.0, F = 0.0

Expected grades: 0,0,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4

Using the data above, construct a simple frequency distribution, a relative frequency, cumulative frequency and a percentile

Answer 1

Expected grades: 0,0,1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4

Frequency Table

Frequency is nothng but number of occurances here 0 occurs twice frequency for 0 is 2

Similar way 1 occurs 10 times so frequency for 1 is 10

Relative frequency = frequnecy / N

N = 50

For 0 , Frequency = 2 Relative Frequency = 2/50 = 0.04

Similar way

For 1 , Frequency = 10 Relative Frequency = 10/50 = 0.2

Cumulative frequency : Sum of all previous frequency

For 0 , Frequency = 2 , Cumulative Frequency = 2

For 1 , Frequency = 10 , Cumulative Frequency = 2+10 =12

Similar way,

For 2 , Frequency = 10 , Cumulative Frequency = 12+10 = 22

Percentile :

For 0 , Frequency = 2 , Cumulative Frequency = 2

Percentile =( 2/50)x100% = 0.04*100% = 4%

For 1 , Frequency = 10 , Cumulative Frequency = 12

Percentile =( 12/50)x100% = 0.24*100% = 24%

For 2 , Frequency = 10 , Cumulative Frequency = 22

Percentile =( 22/50)x100% = 0.44*100% = 44%

Similar way found others.