The mean ( average ) is given as 1200 hours.
The standard deviation is 200, sample size is 100.
Find the standard error:
√(200^2 / 100) = 20
Now calculate the confidence interval. For 95% the Z number is 1.96
Multiply Z by the standard error:
1.96 x 20 =39.2
Now find the range that the mean should be within:
1200 - 39.2 = 1160.8
1200 + 39.2 = 1239.2
The samples should be between 1160.8 and 1239.2 for a 95% confidence interval.
Since the average was 1050, which is below 1160.8 the bulbs are not in compliance.
Answer:
Step-by-step explanation:
first
3/10 & 7/10
second
5/9 & 4/9
Step-by-step explanation:
4/5 gallons for 280 ft² (the ² is missing in the question ...).
3 gallons would be 15/5.
so, what do I need to multiply 4 with to get 15 ?
4×x = 15
x = 15/4
multiplying now also 280 ft² with this factor gives us the answer :
280 × 15/4 = 70 × 15 = 1050 ft²
they can paint 1050 ft² with 3 gallons of paint.
The answer is C because when adding two negatives it equals a positive
Answer:
D
Step-by-step explanation:
