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:
50%
Step-by-step explanation:
So there are 90 2 digit numbers. There are 45 2 digit odd numbers.
The probability should be 50%
Answer:
d because the fomula is always (x,y)
So 6.5 inches long in scale, but every 2 in is 5 yards.
Divide 6.5 by 2. This gives you 3.25. Then multiply by 5 to get yards.
It’s 16.25 yards long.
7x-4=5x+15
-5x on both sides
2x-4=15
add four to both sides
2x=19
divide both sides by 2 to isolate x
x=9.5