A research study examined the blood vitamin D levels of the entire US population of landscape gardeners. The population average level of vitamin D in US landscapers was found to be 30.8 ng/mL with a standard deviation of 4.371 ng/mL. Assuming the true distribution of blood vitamin D levels follows a normal distribution, if you randomly select a landscaper in the US, what is the likelihood that his/her vitamin D level will be between 36.84 and 39.73 ng/mL

0.0631 = 6.31% probability that his/her vitamin D level will be between 36.84 and 39.73 ng/mL

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean and standard deviation , the z-score of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

The population average level of vitamin D in US landscapers was found to be 30.8 ng/mL with a standard deviation of 4.371 ng/mL

This means that

What is the likelihood that his/her vitamin D level will be between 36.84 and 39.73 ng/mL?

This is the pvalue of Z when X = 39.73 subtracted by the pvalue of Z when X = 36.84.

X = 39.73

has a pvalue of 0.9793

X = 36.84

has a pvalue of 0.9162

0.9793 - 0.9162 = 0.0631

0.0631 = 6.31% probability that his/her vitamin D level will be between 36.84 and 39.73 ng/mL

5/12, or 5: 12

step-by-step explanation:

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.