Question

K

The mean percent of childhood asthma prevalence in 43 cities is 2.38%. A random sample of 31 of these cities is selected. What is the probability that the mean childhood asthma
prevalence for the sample is greater than 2.8 % ? Interpret this probability. Assume that o=1.40%.
The probability is
(Round to four decimal places as needed.)
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#
√i
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i
(0,0)
3
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033
Exit session
Dec 2 2:44 O

Answer 1

P(X > 2.6) = 0.0475 = 4.75%

Explanation:

Let X is the random variable that represents percent of childhood asthma prevalence.

We want to find out the probability that the mean childhood asthma prevalence for the sample is greater than 2.6%

The z-score corresponding to 1.67 is 0.9525

P(X > 2.6) = 1 - 0.9525

P(X > 2.6) = 0.0475

P(X > 2.6) = 4.75%

Therefore, there is 4.75% probability that the mean childhood asthma prevalence for the sample is greater than 2.6%

How to use z-table?

Step 1:

In the z-table, find the two-digit number on the left side corresponding to your z-score. (e.g 1.6)

Step 2:

Then look up at the top of z-table to find the remaining decimal point in the range of 0.00 to 0.09. (e.g. if you are looking for 1.67 then go for 0.07 column)

Step 3:

Finally, find the corresponding probability from the z-table at the intersection of step 1 and step 2.