An important problem in industry is shipment damage. a windshield factory ships its product by truck and determines that it cannot meet its profit expectations if, on average, the number of damaged items per truckload is greater than 12. a random sample of 12 departing truckloads is selected at the delivery point and the average number of damaged items per truckload is calculated to be 9.4 with a calculated sample of variance of 0.64. select a 99% confidence interval for the true mean of damaged items.
a) [8.682, 10.12]
b) [39.48. -25.66]
c) [11.28, 12.72]
d) l-0.7181.0.7181
e) [8.707, 10.09]
f) none of the above

Option f) None of these

Step-by-step explanation:

We are given the following data set:

Sample size, n = 12

Sample mean  = 9.4

Sample standard deviation = 0.64

Confidence interval:

Putting the values, we get,

66.666666667%

step-by-step explanation:

divide 150 by 100

divide 100 by 1.5

there you go!

decreased by 33.333333334%

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.