NEED HELP ASAP laboratory tests show that the lives of light bulbs are normally distributed with a mean of 750 hours and a standard deviation of 75 hours. find the probability that a randomly selected light bulb will last between 900 and 975 hours.

0.0214

Step-by-step explanation:

We can get these answer by finding the z-scores at first

Mathematically;

z-score = x-mean/sd

For 900;

z-score = 900-750/75 = 150/75 = 2

For 975

z-score = (975-750)/75 = 3

So the probability we want to calculate is;

P(2<x<3)

This can be calculated using the standard normal distribution table

From the standard score table;

P(2<x<3) = 0.0214

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.

false

step-by-step explanation: