The phrasing "nine times out of ten" means 9/10 = 0.90 = 90% is the confidence level. We're confident 90% of the time that the confidence interval captures the population parameter we're after (in this case mu = population mean)
The portion "have an average score within 5% of 75%" means that 75% = 0.75 is the center of the confidence interval, and it goes as low as 0.75 - 0.05 = 0.70 and as high as 0.75 + 0.05 = 0.80
This confidence interval is from 70% to 80%, meaning that nine times out of ten, we're confident that the average score is between 70% and 80%
We write the confidence interval as (0.70, 0.80). It's common to use the notation (L, U) to indicate the lower (L) and upper (U) boundaries. You might see the notation in the form L < mu < U. If so, then it would be 0.70 < mu < 0.80; either way they mean the same thing.
The margin of error is 0.05 as its the 5% radius of the interval. It tells us how far the most distant score is from the center (75%)
=========================================
In summary, we have these answers
- confidence level = 90%
- margin of error = 5% = 0.05
- confidence interval = (0.70, 0.80)
- interpretation = We're 90% confident that the average exam score is between 0.70 and 0.80
It would cost $38.40 because if you do $1.60 times 24 you get 38.4
Answer:
Test statistics = 2.85
P-value = 0.002
Step-by-step explanation:
We are given that a sporting goods store believes the average age of its customers is 38 or less.
A random sample of 40 customers was surveyed, and the average customer age was found to be 41.6 years and the standard deviation for customer age is 8.0 years.
Null Hypothesis, 
: 
<= 38 years
Alternate Hypothesis, 
: > 38 years
The test statistics we will use here is;
T.S. = 
~ N(0,1)
where, X bar = sample mean = 41.6 years
= population standard deviation = 8 years
n = sample size = 40
So, test statistics = 
= 2.85
At 5% level of significance, the z table gives critical value of 1.6449. Since our test statistics is more than the critical value of z so we have sufficient evidence to reject the null hypothesis and conclude that average age of its customers is more than 38 years.
P-value is given by, P(Z > 2.85) = 1 - P(Z <= 2.85) = 1 - 0.99781 = 0.002 .
Answer:
4th option
Step-by-step explanation:
brainliest plsssss
The numbers are 2, 2, 4, 5, 7
