A study indicates that teenagers spend an average of 112 minutes watching videos on their smartphones per week. Assume the distribution is normal, with a standard deviation of 12 minutes. What is the probability that a teenager spends less than 90 minutes watching videos on their phone per week

0.0336 = 3.36% probability that a teenager spends less than 90 minutes watching videos on their phone per week.

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.

A study indicates that teenagers spend an average of 112 minutes watching videos on their smartphones per week. Assume the distribution is normal, with a standard deviation of 12 minutes.

This means that

What is the probability that a teenager spends less than 90 minutes watching videos on their phone per week?

This is the p-value of Z when X = 90. So

has a p-value of 0.0336

0.0336 = 3.36% probability that a teenager spends less than 90 minutes watching videos on their phone per week.

x=-2

infinite number of lines, so there is an infinite number of equations.

step-by-step explanation:

there are an infinite number of line that passes through the point (-2,5)

x=-2   is one line that passes through the point

y = 5 is another line that passes through the point

(these two lines are perpendicular to each other).

since the number of   numbers are infinite and the slope is the ratio of two numbers,(change in y over change in x) we can have an infinite number of slopes.     our only condition is that it passes through the point (-2,5)