This is all I need because its 55% of my grade on this practice, please help ty.
1 answer:
Answer:
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Step-by-step explanation:
First question:
He starts with 18, gains 2 every week, and needs 42. This means the equation is .
Second question:
He starts with 2, gains 18 every week, and needs 42. This means the equation is .
Third question:
It starts with 42, loses 2 every day, and needs 18. This means the equation is .
Fourth question:
Each friend has a total bill of 18+x, there are 2 friends, and they need 42. This means the equation is .
The only answer left is , so that's the answer to the fifth problem.
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This is basically how you do it if you need more help let me know
This is basically how you do it if you need more help let me know
Answer:
a) The expected value of the sample mean weight is 20.4 pounds.
b)The standard deviation of the sample mean weight is 0.123.
c) There is a 14.46% probability the sample mean weight will be less than 20.27.
d) This value is .
Step-by-step explanation:
The Central Limit Theorem estabilishes that, for a random variable X, with mean and standard deviation
, a large sample size can be approximated to a normal distribution with mean
and standard deviation
.
Problems of normally distributed samples can be solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
A particular variety of watermelon weighs on average 20.4 pounds with a standard deviation of 1.23 pounds. This means that
Consider the sample mean weight of 100 watermelons of this variety. This means that .
a. What is the expected value of the sample mean weight? Give an exact answer.
By the Central Limit Theorem, it is the same as the mean of the population. So the expected value of the sample mean weight is 20.4 pounds.
b. What is the standard deviation of the sample mean weight? Give your answer to four decimal places.
By the Central Limit Theorem, that is:
The standard deviation of the sample mean weight is 0.123.
c. What is the approximate probability the sample mean weight will be less than 20.27?
This is the pvalue of Z when .
Since we are working with the sample mean, we use instead of
in the Z score formula
has a pvalue of 0.1446.
This means that there is a 14.46% probability the sample mean weight will be less than 20.27.
d. What is the value c such that the approximate probability the sample mean will be less than c is 0.96?
This is the value of that is in the 96th percentile, that is, it's Z score has a pvalue 0.96.
So we use
This value is .