Answer:
The last option
Step-by-step explanation:
Trust me, I know it is correct
Answer:
151 students must be selected.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 1.96.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
The population standard deviation is known to be $25.
This means that
How many students must be randomly selected to estimate the mean weekly earnings of students at one college? Sample mean within $4 of the population mean
This is n for which M = 4. So
Rounding up:
151 students must be selected.
Subtract 13 from both sides of the equation.
Answer:
0.5466
Step-by-step explanation:
Given that the length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 16 days.
Let X be the length of pregnancies
X is N(266,16)
To find out the probability that pregnancies last between 240 and 270 days (roughly between 8 months and 9 months)
P(240<x<270)
convert each into Z score as
x=240 means Z = -1.625
x=270 means z=0.25
Required prob
=
Answer:
14
Step-by-step explanation:
6(2)
12
4÷2
2
12+2
pemdas