Answer: 0.5467
Step-by-step explanation:
We assume that the test scores for adults are normally distributed with
Mean : 
Standard deviation : 
Sample size : = 50
Let x be the random variable that represents the IQ test scores for adults.
Z-score : 
For x =85

For x =115

By using standard normal distribution table , the probability the mean of the sample is between 95 and 105 :-

Hence, the probability that a randomly selected adult has an IQ between 85 and 115 =0.5467
Answer: It is 950
Step-by-step explanation:
Answer:
The radius is decreatsing at a rate 0.78 cm per second.
Step-by-step explanation:
We are given the following in the question:

Instant radius,r = 2 cm
Instant length,l = 9cm
The radius of the cylinder decreases.
Volume of cylinder =

Since the volume of the cylinder does not changes, we can write:

Rate of change of volume:

Puttiung values, we get

Thus, the radius is decreatsing at a rate 0.78 cm per second.
Answer:
The standard deviation for the number of students who work full time = 8.38
Step-by-step explanation:
Given data
Sample size n = 284
No. of students work full time is P = 55 % = 0.55
No. of students who not work full time is Q = 100- 55 % = 45 % = 0.45
The standard deviation is given by

Put all the values in above equation we get

S.D. = 8.38
This is the standard deviation for the number of students who work full time.
If it’s supposed to be perpendicular then it has to have a negative 1 somewhere