Samantha sends her son, Barry, to a preschool center on certain days. The cost of preschool is $45 per day along with a fixed mo
1 answer:
Answer: Option D
D. 880 = 45d + 70; 18 days
Step-by-step explanation:
We know that the cost of preschool is $ 45 per day plus a monthly fee of $ 70.
We also know that a total of $ 880 was paid last month
To write an equation that represents this situation, let us call d the number of days that Barry attends school
So the cost was:
Now we solve the equation for the variable d
The answer is the option D
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Answer:
Step-by-step explanation:
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The t distribution or Student’s t-distribution is a "probability distribution that is used to estimate population parameters when the sample size is small (n<30) or when the population variance is unknown".
The shape of the t distribution is determined by its degrees of freedom and when the degrees of freedom increase the t distirbution becomes a normal distribution approximately.
Data given
Confidence =0.99 or 99%
represent the significance level
n =16 represent the sample size
We don't know the population deviation
Solution for the problem
For this case since we don't know the population deviation and our sample size is <30 we can't use the normal distribution. We neeed to use on this case the t distribution, first we need to calculate the degrees of freedom given by:
We know that so then
and we can find on the t distribution with 15 degrees of freedom a value that accumulates 0.005 of the area on the left tail. We can use the following excel code to find it:
"=T.INV(0.005;15)" and we got on this case since the distribution is symmetric we know that the other critical value is