Answer:
So we use the t-distribution to compute a confidence interval for the average age of people using online dating services
Step-by-step explanation:
Confidence interval for a mean.
We have to decide between the t-distribution and the z-distribution.
T-distribution: We use the sample standard deviation.
Z-distribution: We use the population standard deviation.
In this problem:
The average age of those that were using online dating services was 35 years old with a sample standard deviation of 12 years.
So we use the t-distribution to compute a confidence interval for the average age of people using online dating services
Answer:
12√5
Step-by-step explanation:
According to the attached sketch, there are 2 triangles which we need to focus on, triangle A (in yellow) and triangle B (In red).
If you look at triangle A, we notice that X is the hypotenuse of triangle A. This means that X must be the largest length in triangle A, hence we can say that x must be greater than 24 (or 24 < x)
Now look at triangle B, in this case, they hypotenuse is 30 and x is the length of one of the sides. This means that x must be shorter than the hypotenuse (i.e x < 30)
from the 2 paragraphs above, we can see now that we can assemble an inequality in x
24 < x < 30
If we look at the choices, we can immediately ignore 33 because x must be less than 30,
working out the choices, we find that the only choice which falls into the range 24<x<30 is the 2nd choice 12√5 (= 26.83) (which is the answer)
The last 2 choices give values smaller than 24 and are hence cannot be the answer
Answer:
The expression means that X+20
The probability that the next 4 winners will all be 7th grade students is 3/4