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leva [86]
2 years ago
9

A GE lightbulb is supposed to last for 1,200 hours. In fact, light bulbs of this type last only 1,185 hours with a standard devi

ation of 70 hours. What is the probability that a sample of 100 lightbulbs will have an average life of at least 1,200 hours? Mathematics
Mathematics
1 answer:
dybincka [34]2 years ago
7 0
This can be solved using the formula for t test which is = x - mu over standard deviation divided by the square root of the number of samples. In this case, it is 1185 - 1200 over 70 divided by square root of 100 which give us a value of 2.14 which is equal to .9839 in area. Only rarely, just over one time in a hundred tries of 100 light bulbs, would the average life exceed 1200 hours.
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Answer:

Accuracy = 0.81

Sensitivity = 0.93

Specificity = 0.81

Precision = 0.047

Step-by-step explanation:

Given the confusion matrix :

Actual_______ Donation___ No Donation

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Accuracy is calculated as :

(TP + TN) / (TP+TN+FP+FN)

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ACCURACY = (23707 / 29102) = 0.81

Sensitivity (True positive rate) :

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268 ÷ 288 = 0.93

Specificity (True Negative rate) :

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Precision :

TP ÷ (TP + FP)

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2 years ago
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I mean, it says it in the question.

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