Answer:
Hope this helps
Step-by-step explanation:
Answer:
( $74.623, $83.777)
The 90% confidence interval is = ( $74.623, $83.777)
Critical value at 90% confidence = 1.645
Step-by-step explanation:
Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.
The confidence interval of a statistical data can be written as.
x+/-zr/√n
Given that;
Mean x = $79.20
Standard deviation r = $10.41
Number of samples n = 14
Confidence interval = 90%
Using the z table;
The critical value that should be used in constructing the confidence interval.
z(α=0.05) = 1.645
Critical value at 90% confidence z = 1.645
Substituting the values we have;
$79.20+/-1.645($10.42/√14)
$79.20+/-1.645($2.782189528308)
$79.20+/-$4.576701774067
$79.20+/-$4.577
( $74.623, $83.777)
The 90% confidence interval is = ( $74.623, $83.777)
Well the solution to this problem is x < -4
If it’s just (-4) with nothing in front the answer is -4
Answer B.
∑fx=1637,∑fx
2
=127663,∑f=21
x
ˉ
=Mean=
∑t
∑fx
=77.95
σ
2
=
∑f
∑fx
2
−(
x
ˉ
)
2
=
21
127663
−(77.95)
2
=2.987
σ=1.728
