Answer:
a) The mean is 
b) The standard deviation is 
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions 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.
The probability a student selected at random takes at least 55.50 minutes to complete the examination equals 0.6915.
This means that when X = 55.5, Z has a pvalue of 1 - 0.6915 = 0.3085. This means that when 
So




The probability a student selected at random takes no more than 71.52 minutes to complete the examination equals 0.8997.
This means that when X = 71.52, Z has a pvalue of 0.8997. This means that when 
So




Since we also have that 





Question
The mean is 
The standard deviation is 
Answer:
what is the question. please provide a question.
Answer:
Step-by-step explanation:
f-1(x)=arcsin x- (x/2)
Do the -1 small on top of f in the left hand side
Answer:
<em>Question 7. Option B,</em>
<em>Question 8. Option C</em>
Step-by-step explanation:
<em>Question 7.</em>
Let us create a proportionality, and solve for the value of s, through cross multiplication;

<em>Question 8.</em>
We can solve this problem in a similar manner, through setting a proportionality and solving for the length of the shadow of the tree, which we can pose as x;

Answer:
an equal-groups problem because the problem mentions that each friend gets an equal amount
Step-by-step explanation:
The multiplication and division operations work for these types of problems