Answer:
The approximate 90% confidence interval is;
70,244 to 70,732
Step-by-step explanation:
Here, we want to calculate the approximate 90% C.I for the situation
Mathematically;
CI = mean ± (z * SD)/√n
From the question;
mean = 70,438
SD = 645.3
n = 30
we can get z from the CI table
90% CI is same as; 1.645 z-score
So , substituting these values;
CI = 70,438 ± ( 1.645 * 645.3)/√30
CI = 70,438 ± 194
So the CI = 70,438 -194 to 70,438 + 194
= 70,244 to 70,732
I’m not completely sure but I think the answer is C.
Answer:
17.3
Step-by-step explanation:
50 - 32.7 = 17.3
Answer:
Mean = 1.42
Variance = 0.58
Step-by-step explanation:
Given: X denote the number of luxury cars sold in a given day, and Y denote the number of extended warranties sold.
Also, joint probability function of X and Y are given.
To find:
mean and variance of X
Solution:
From the given joint probability function of X and Y,
Mean of X:
Variance of X:
![var(X)=E\left [ X^2 \right ]-\left ( E\left [ X \right ] \right )^2\\=\frac{31}{12}-\left ( \frac{17}{12} \right )^2\\=\frac{31}{12}-\frac{289}{144}\\=\frac{372-289}{144}\\=\frac{83}{144}\\=0.58](https://tex.z-dn.net/?f=var%28X%29%3DE%5Cleft%20%5B%20X%5E2%20%5Cright%20%5D-%5Cleft%20%28%20E%5Cleft%20%5B%20X%20%5Cright%20%5D%20%5Cright%20%29%5E2%5C%5C%3D%5Cfrac%7B31%7D%7B12%7D-%5Cleft%20%28%20%5Cfrac%7B17%7D%7B12%7D%20%5Cright%20%29%5E2%5C%5C%3D%5Cfrac%7B31%7D%7B12%7D-%5Cfrac%7B289%7D%7B144%7D%5C%5C%3D%5Cfrac%7B372-289%7D%7B144%7D%5C%5C%3D%5Cfrac%7B83%7D%7B144%7D%5C%5C%3D0.58)
Answer:
$580
Step-by-step explanation:
Original price = $156.60 / 0.27
Original price = $580
