Answer: (14.4, 17.2)
Step-by-step explanation: We are to construct a 98% confidence interval for mean household usage of electricity.
We have been given that
Sample size (n) = 872
Sample mean (x) = 15.8
Population standard deviation (σ) = 1.8
The formulae that defines the 98% confidence interval for mean is given below as
u = x + Zα/2 × σ/√n...... For the upper limit
u = x - Zα/2 × σ/√n...... For the lower limit
Zα/2 = critical value for a 2% level of significance in a two tailed test = 2.33
By substituting the parameters we have that
For upper tailed
u = 15.8 + 2.33 × (1.8/√872)
u = 15.8 + 2.33 (0.6096)
u = 15.8 + 1.4203
u = 17.2
For lower tailed
u = 15.8 - 2.33 × (1.8/√872)
u = 15.8 - 2.33 (0.6096)
u = 15.8 - 1.4203
u = 14.4
Hence the 98% confidence interval for population mean usage of electricity is (14.4kwh, 17.2kwh)
Answer:the answer is 9
Step-by-step explanation:
36 divided by 4=9
Answer:
Its x cause it has no value yet
Step-by-step explanation:
Answer:
<u>The correct answer is D. x + 5≤ - 4</u>
Step-by-step explanation:
Let's review which inequality has - 12 in its solution set, this way:
A. x + 6 less-than negative 8
-12 + 6 < - 8
-6 < - 8 Not correct
B. x + 4 greater-than-or-equal-to negative 6
- 12 + 4 ≥ - 6
- 8 ≥ - 6 Not correct
C. x minus 3 greater-than negative 10
- 12 - 3 > - 10
<u>- 15 > - 10 Not correct</u>
D. x + 5 less-than-or-equal-to negative 4
- 12 + 5 ≤ - 4
- 7 ≤ - 4 This is correct
<u>The correct answer is D. x + 5≤ - 4</u>
