1. A sample consists of 75 TV sets purchased several years ago. The replacement times of those TV sets have a mean of 8.2 years.
1 answer:
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Answer:
0.8762 or 87.62%
Step-by-step explanation:
Since our mean is μ=14.3 and our standard deviation is σ=3.7. If we're trying to figure out what percentage is P(10 ≤ x ≤ 26) equal to we must first calculate our z values as such:
Our x value ranges from 10 to 26 therefore let x=10 and we obtain:
If we look at our z-table we find that the probability associated with a z value of -1.16 is 0.1230 meaning 12.30%.
Now let's calculate the z value when x = 26 and so:
Similarly, we use the z-table again and find that the probability associated with a z value of 3.16 is 0.9992 meaning 99.92%.
Now we want to find the probability in between 10 and 26 so we will now subtract the upper limit minus the lower limit in P(10 ≤ x ≤ 26) therefore:
0.9992 - 0.1230 = 0.8762
or 87.62%