Answer:
The probability that <em>X</em> is less than 42 is 0.1271.
Step-by-step explanation:
The random variable <em>X </em>follows a Normal distribution.
The mean and standard deviation are:
E (X) = <em>μ</em> = 50.
SD (X) = <em>σ</em> = 7.
A normal distribution is continuous probability distribution.
The Normal probability distribution with mean µ and standard deviation σ is given by,

To compute the probability of a Normal random variable we first standardize the raw score.
The raw scores are standardized using the formula:

These standardized scores are known as <em>z</em>-scores and they follow normal distribution with mean 0 and standard deviation 1.
Compute the probability of (X < 42) as follows:

*Use a <em>z</em>-table for the probability.
Thus, the probability that <em>X</em> is less than 42 is 0.1271.
The normal curve is shown below.
Answer:
Equation of line best fits the scatter plot is y =
Step-by-step explanation:
Let the equation of line be y = mx + c
where m = slope of line and c is the intercept on y -axis
from the graph intercept on y-axis is 108
and the slope of line is given by m =
where (
) and (
) is the points on line
let, points be (4,96) and (18,36)
on calculating this m =
= 
Therefore equation of line best fits the scatter plot is y =
Answer:
try right 3, up 4. if not, try right 4, up 3.
X stands for the score of her first test
Y stands for the score of her second test