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 
It is impossible to draw a parallelogram with 4 parallel lines (or to draw any quadrilateral with 4 parallel lines, for that matter).
Answer:
Let S = starting point
Let ST = length of tunnel
SR = 1414 m
RT = 2236 m
Set up:
ST^2 + SR^2 = RT^2
ST^2 + (1414)^2 = (2236)
Solve for RT to find your answer.
Step-by-step explanation:
You are correct C. is the answer.
2r + 2r + 5 + r + 4r - 3 = 38
9r + 5 - 3 = 38
9r + 2 = 38
9r = 38 - 2
9r = 36
9r/9 = 36/9
r = 4cm
Done!