using excel add ins tool PHStat, folllowing o/p is obtained,
| Chi-Square Test | ||||||
| Observed Frequencies | ||||||
| Column variable | Calculations | |||||
| Row variable | white | Black | Total | fo-fe | ||
| section A | 92 | 11 | 103 | 9.40566 | -9.40566 | |
| section B | 78 | 31 | 109 | -9.40566 | 9.40566 | |
| Total | 170 | 42 | 212 | |||
| Expected Frequencies | ||||||
| Column variable | ||||||
| Row variable | white | Black | Total | (fo-fe)^2/fe | ||
| section A | 82.59434 | 20.40566 | 103 | 1.071096 | 4.335388 | |
| section B | 87.40566 | 21.59434 | 109 | 1.012136 | 4.096742 | |
| Total | 170 | 42 | 212 | |||
a) chi square stat = Σ(fo-fe)^2/fe = 10.515
df=(row-1)(column-1) = 1
p-value = 0.001
b)
first sample size, n1= 103
number of successes, sample 1 = x1=
92
proportion success of sample 1 , p̂1=
x1/n1= 0.893203883
second sample size, n2 = 109
number of successes, sample 2 = x2 =
78
proportion success of sample 1 , p̂ 2= x2/n2 =
0.71559633
difference in sample proportions, p̂1 - p̂2 =
0.177607553
pooled proportion , p = (x1+x2)/(n1+n2)=
0.801886792
std error ,SE = =SQRT(p*(1-p)*(1/n1+ 1/n2)
0.054770829
Z-statistic = (p̂1 - p̂2)/SE =
3.24
p-value=0.001
----------------------------
c)
we can observe that
Z stat ^2 = chi square stat
3.24² = 10.515
so, answer is option c)
-----------------
d)
we can observe that, two p-values are equal.
answer: option b
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Interval 1:
z
≤−1.0
Interval 2:−1.0
<
z
≤
0
Interval 3:
0
<
z...
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