Question

Given a normal distribution with mu equals 100 and sigma equals 10 comma complete parts​ (a) through​ (d). LOADING... Click here to view page 1 of the cumulative standardized normal distribution table. LOADING... Click here to view page 2 of the cumulative standardized normal distribution table. a. What is the probability that Upper X greater than 70​? The probability that Upper X greater than 70 is .0016 nothing. ​(Round to four decimal places as​ needed.) b. What is the probability that Upper X less than 80​? The probability that Upper X less than 80 is nothing. ​(Round to four decimal places as​ needed.) c. What is the probability that Upper X less than 95 or Upper X greater than 125​? The probability that Upper X less than 95 or Upper X greater than 125 is nothing. ​(Round to four decimal places as​ needed.) d. 99​% of the values are between what two​ X-values (symmetrically distributed around the​ mean)? 99​% of the values are greater than nothing and less than nothing.

Answer 1

Refer Z-table to find the probability or use excel formula "=NORM.S.DIST(-3, TRUE)" to find the probability.

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Refer Z-table to find the probability or use excel formula "=NORM.S.DIST(-2, TRUE)" to find the probability.

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Use addition rule,

Refer Z-table to find the probability or use excel formula "=NORM.S.DIST(-0.5, TRUE)" & "=NORM.S.DIST(2.5, TRUE)" to find the probability.

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Refer Z-table, Lookup for Z-value corresponding to area 0.995 to the left of the normal curve or use excel formula "=NORM.S.INV(0.995)" to find the Z-value.