Answer:
Yes, the mean number is more than 40
Step-by-step explanation:
The null hypothesis
H0 = mean is 40
Let´s make the t test
t = (x – mean) / standard deviation / √sample size
t = (42 – 40) / 2.1 / √28
t = 5.039
now we find t value for one tail, using a T-distribution table
df = n – 1 = 27
α = 0.05
so, t = 1.703
since our calculated t value is greater than the t for the table, the null hypothesis can be rejected. So the mean number of calls per salesperson per week is more than 40.
Answer: 18 c
Step-by-step explanation: since they have the same variables you can easily just add them together
Complete Question
You are organizing books on a shelf. Each book has a width of 3/4 inch. The number of shelves is 12.
Write and solve an inequality for the numbers of books b that can fit on the shelf.
Answer:
a) Inequality for the numbers of books b that can fit on the shelf
= b ≤ 3x/4
b) The numbers of books b that can fit on the shelf is b ≤ 9 books
Step-by-step explanation:
Let the number of books = b
Let us assume the number of shelves= x
Each book has a width of 3/4 inch.
Therefore,
b ≤ 3/4 × x
b ≤ 3x/4
If the number of the shelves is 12
Therefore, the number of books bis
b ≤ 3 × 12/4
b ≤ 9 books
Answer:
70.94 mm is the upper control level with a 99.7% level of confidence.
Step-by-step explanation:
We are given the following data:
69, 72, 71, 70, 68
Population mean = 70 mm
Population standard deviation = 1.25 mm
We have to find the upper control level with a 99.7% level of confidence.
![Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}](https://tex.z-dn.net/?f=Mean%20%3D%20%5Cdisplaystyle%5Cfrac%7B%5Ctext%7BSum%20of%20all%20observations%7D%7D%7B%5Ctext%7BTotal%20number%20of%20observation%7D%7D)
![Mean =\displaystyle\frac{350}{5} = 70](https://tex.z-dn.net/?f=Mean%20%3D%5Cdisplaystyle%5Cfrac%7B350%7D%7B5%7D%20%3D%2070)
99.7% Confidence interval:
![\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=%5Cmu%20%5Cpm%20z_%7Bcritical%7D%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
Putting the values, we get,
![z_{critical}\text{ at}~\alpha_{0.003} = \pm 2.98](https://tex.z-dn.net/?f=z_%7Bcritical%7D%5Ctext%7B%20at%7D~%5Calpha_%7B0.003%7D%20%3D%20%5Cpm%202.98)
![70 \pm 2.98(\frac{1.25}{\sqrt{16}} ) = 70 \pm 0.93125 = (69.06875,70.93125) \approx (69.07,70.94)](https://tex.z-dn.net/?f=70%20%5Cpm%202.98%28%5Cfrac%7B1.25%7D%7B%5Csqrt%7B16%7D%7D%20%29%20%3D%2070%20%5Cpm%200.93125%20%3D%20%2869.06875%2C70.93125%29%20%5Capprox%20%2869.07%2C70.94%29)
Thus, 70.94 mm is the upper control level with a 99.7% level of confidence.