In: Statistics and Probability
In a certain city, there are about one million eligible voters. A simple random sample of size 10,000 was chosen to study the relationship between gender and participation in the last election. The results were: In a certain city, there are about one million eligible voters.
Men | Women | |
Voted |
2499 |
3311 |
Didn't Vote |
1722 |
2468 |
If we are testing for a relationship between gender and
participation in the last election, what is the p-value and
decision at the 5% significance level? Select the [p-value,
Decision to Reject (RH0) or Failure to Reject
(FRH0)] If we are testing for a relationship between
gender and participation in the last election, what is the p-value
and decision at the 5% significance level? Select the [p-value,
Decision to Reject (RH0) or Failure to Reject (FRH0)]
a) [p-value = 0.056, FRH0]
b) [p-value = 0.301, FRH0]
c) [p-value = 0.056, RH0]
d) [p-value = 0.301, RH0]
e) [p-value = 0.028, RH0]
SOLUTION:
From given data,
A simple random sample of size 10,000
Add up rows and columns:
Men | Women | Total | |
Voted | 2499 | 3311 | 5810 |
Didn't Vote | 1722 | 2468 | 4190 |
Total | 4221 | 5779 | 10000 |
Calculate "Expected Value" for each entry:
Multiply each row total by each column total and divide by the overall total:
Men | Women | |
Voted | 5810*4221 / 10000 = 2452.401 | 5810*5779 / 10000 = 3357.599 |
Didn't Vote | 4190*4221 / 10000 = 1768.599 | 4190*5779 / 10000 = 2421.401 |
Subtract expected from actual, square it, then divide by expected:
=
Men | Women | |
Voted |
(2499-2452.401)2 / 2452.401 =0.885445 |
(3311-3357.599)2 / 3357.599 =0.646732 |
Didn't Vote |
(1722-1768.599)2 / 1768.599 =1.227789 |
(2468-2421.401)2 / 2421.401 = 0.896781 |
Now add up those values:
0.885445+0.646732+1.227789+0.896781 = 3.656747
Chi-Square = = 3.656747
From Chi-Square to p
Calculate Degrees of Freedom
= (rows − 1) (columns − 1)
DF = (2 − 1)(2 − 1) = 1×1 = 1
P- value at = 3.65674 with DF = 1
P- value = 0.05584280
approx , P- value = 0.056
at 5% significance level that is
= 0.05
P- value >
Failure to Reject null hypothesis
Answer is a) [p-value = 0.056, [FRH0]