The formula for the confidence interval is given by
Sample mean + z*[σ/√n], and
Sample mean - z*[σ/√n]
We have:
Sample mean = 23.95
n = 40
σ = 2.55
z* for 99% confidence = 2.58
Substitute these values into the formula, we have
23.95 + (2.58)(2.55÷√40) = 24.99
23.95 - (2.58)(2.55÷√40) = 22.91
So the lower interval is 22.91 and the highest interval is 24.99
Answer:
c
Step-by-step explanation:
In this equation, you have to treat the number in the bracket first on the basis of BODMAS
15 - [-3]- 4
Note that when two minuses come together the product is a plus sign.
15 +3 - 4
You have to add before you subract
18 - 4 =14
Therefore, 15- [-3] - 4 = 14.
The average is found by adding the numbers and dividing by 2.
Since the average is 17, the total of the two numbers must equal 17 x 2 = 34.
One number is given as 11, so subtract 11 from 34:
34 - 11 = 23
The other number is 23.
Too check: add 11 and 23 and then divide by 2:
11 + 23 = 34
34/2 = 17.
