University:
Jackson College
Course:
MAT-010 | Basic Mathematics
Academic year:

2024
Views:

59

Pages:

2
Author:

Bennett Wheeler

Question 1 You randomly survey students at your school about what type of books they like to read. The two-way table shows your results. Find and interpret the marginal frequencies. Fiction Non-Fiction Likes 26 22 Dislikes 20 2 Answer 1 The marginal frequency of a category is found by summing the values in each row or column for that category. The marginal frequencies are: Total students who like Fiction: 26 + 20 = 46 26+20=46 Total students who dislike Fiction: 22 + 2 = 24 22+2=24 Total students who like Non-Fiction: 26 + 22 = 48 26+22=48 Total students who dislike Non-Fiction: 20 + 2 = 22 20+2=22 Thus: 46 students liked Fiction, while 24 disliked it. 48 students liked Non-Fiction, while 22 disliked it. Question 2 The manager of the store in the preceding exercise calculated the residual for each point in the scatterplot and made a dotplot of the residuals. The distribution of residuals is approximately normal with a mean of $0 and a standard deviation of $22.92. A. What percent of the actual sales amount do you expect to be within $5 of their expected sales amount? B. The middle 95% of residuals should lie within what two values? Answer 1 Given that 𝑋 ∼ Normal ( 𝜇 , 𝜎 ) X∼Normal(μ,σ) with 𝜇 = 0 μ=0 and 𝜎 = 22.92 σ=22.92: Part A We want to find the probability that the residual is within $5 of the mean, i.e., − 5 < 𝑋 < 5 −5