Answer:
95% confidence interval for the mean number of months is between a lower limit of 6.67 months and an upper limit of 25.73 months.
Step-by-step explanation:
Confidence interval is given as mean +/- margin of error (E)
Data: 5, 15, 12, 22, 27
mean = (5+15+12+22+27)/5 = 81/5 = 16.2 months
sd = sqrt[((5-16.2)^2 + (15-16.2)^2 + (12-16.2)^2 + (22-16.2)^2 + (27-16.2)^2) ÷ 5] = sqrt(58.96) = 7.68 months
n = 5
degree of freedom = n-1 = 5-1 = 4
confidence level (C) = 95% = 0.95
significance level = 1 - C = 1 - 0.95 = 0.05 = 5%
critical value (t) corresponding to 4 degrees of freedom and 5% significance level is 2.776
E = t×sd/√n = 2.776×7.68/√5 = 9.53 months
Lower limit of mean = mean - E = 16.2 - 9.53 = 6.67 months
Upper limit of mean = mean + E = 16.2 + 9.53 = 25.73 months
95% confidence interval is (6.67, 25.73)
Answer:
a) 
b) 
Step-by-step explanation:
Given that:
population mean
= 30,000
sample size n = 800
population proportion p = 0.6
a)
The mean of the the sampling distribution is equal to the population proportion.


b)
The standard deviation of the sampling distribution can be estimated by using the formula:






Answer:
He bought 7 lightbulbs.
Step-by-step explanation:
37.19 - 3.73 = 33.46
33.46/4.78=7
The answer is 3/4. You divide both numbers (54 and 72) by 18 and you get 3/4. Hope it helps!
Answer:
B. 14 ⁴⁄₁₀
Step-by-step explanation:
I say its b because all u have to do it multiply 6 ⅕ but not the 6, just the 1 and the 5, just multiply by two and both fractions will have the same total amount which is 10 and 6 ⅕ will turn to 6 with 2/10 so all u have to do now is add that fraction to 8 ²⁄₁₀