Question

Based on 2017 sales, the six top-selling compact cars are the Honda Civic, Toyota Corolla, Nissan Sentra, Hyundai Elantra, Chevrolet Cruze, and Ford Focus (New York Daily News). The 2017 market shares are Honda Civic 20%, Toyota Corolla 17%, Nissan Sentra 12%, Hyundai Elantra 10%, Chevrolet Cruze 10%, and Ford Focus 8%, with other small car models comprising the remaining 23%. A sample of 400 compact car sales in Chicago showed the following number of vehicles sold.

Honda Civic 98
Toyota Corolla 72
Nissan Sentra 54
Hyundai Elantra 44
Chevrolet Cruze 42
Ford Focus 25
Others 65

Required:
Use a goodness of fit test to determine whether the sample data indicate that the market shares for cars in Chicago are different than the market shares suggested by nationwide 2017 sales. Using α= 0.05 level of significance, what is the p-value?

Answer 1

1. p value = 0.0203

2. We conclude that the market share for cars are different from what was suggested by the nation wde sales in 2017

Explanation:

first we solve for the chisquare of this data.

from the attachment i have uploaded, a table of the ch square that i calculate gave:

Chisquare = 14.99

n = 7

degree of freedom = 7-1 = 6

we formulate hypothesis

H0; no diference in market share

H1: there is difference in market share

alpha = 0.05

we find the p value using the excel formula

CHIDIST(14.99, 6)

p value = 0.0203

the p value lies between 0.01 and 0.025

so we reject null and conclude that market share for for cars are different from what is suggested by nationwide sales in 2017