Answer:
Step-by-step explanation:
This is a test of 2 population proportions. Let 1 and 2 be the subscript for the men and women who own cats respectively. The population proportion of men and women who own cats would be p1 and p2 respectively.
p1 - p2 = difference in the proportion of men and women who own cats.
The null hypothesis is
H0 : p1 = p2
p1 - p2 = 0
The alternative hypothesis is
Ha : p1 ≠ p2
p1 - p2 ≠ 0
it is a two tailed test
Sample proportion = x/n
Where
x represents number of success
n represents number of samples
For men
n1 = 80
p1 = 55/100 = 0.55
x1 = p1n1 = 0.55 × 80 = 44
For women,
n2 = 100
p2 = 30/100 = 0.3
x2 = p2n2 = 0.3 × 100 = 30
The pooled proportion, pc is
pc = (x1 + x2)/(n1 + n2)
pc = (44 + 30)/(80 + 100) = 0.41
1 - pc = 1 - 0.41 = 0.59
z = (p1 - p2)/√pc(1 - pc)(1/n1 + 1/n2)
z = (0.55 - 0.3)/√(0.41)(0.59)(1/80 + 1/100) = 3.39
Test statistic = 3.39
Answer:
the 24×4 you have to count 4 times
AVERAGE between 90 and 100%
means not including 90 and 100% but not including 90 or 100%
average=(sum of values in set)/(how many values in the set)
so
4 exams, so there are 4 values
average=(sum)/4
the sum is the known+unknwon
sum=76+99+86+x
so
90<span><</span>average and average <span><</span>100
or
90<span><</span>average<span><</span>100
lets say average=a
a=sum/number
a=(76+99+86+x)/4
90<(76+99+86+x)/4<100
90<(76+99+86+x)/4 and (76+99+86+x)/4<100
solve each for x and find intersection
90<span><</span>(76+99+86+x)/4
times 4 both sides
360<span><</span>261+x
minus 261 both sides
99<span><</span>x
(76+99+86+x)/4<u><</u>100
times 4 both sides
261+x<u><</u>400
minus 261 both sides
x<u><</u>139
so
99<u><</u>x<u><</u>139
since max score is 100
99<u><</u>x<u><</u>100
interval notaion is
[99,100]
answer is 2nd one
