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:
Step-by-step explanation:
Area = 1/2 b h
= 1/2 * 4 * 5
= 10 unit^2.
Answer:
Step-by-step explanation:
Given the explicit function as
f(n) = 15n+4
The first term of the sequence is at when n= 1
f(1) = 15(1)+4
f(1) = 19
a = 19
Common difference d = f(2)-f(1)
f(2) = 15(2)+4
f(2) = 34
d = 34-19
d = 15
Sum of nth term of an AP = n/2{2a+(n-1)d}
S20 = 20/2{2(19)+(20-1)15)
S20 = 10(38+19(15))
S20 = 10(38+285)
S20 = 10(323)
S20 = 3230.
Sum of the 20th term is 3230
For the explicit function
f(n) = 4n+15
f(1) = 4(1)+15
f(1) = 19
a = 19
Common difference d = f(2)-f(1)
f(2) = 4(2)+15
f(2) = 23
d = 23-19
d = 4
Sum of nth term of an AP = n/2{2a+(n-1)d}
S20 = 20/2{2(19)+(20-1)4)
S20 = 10(38+19(4))
S20 = 10(38+76)
S20 = 10(114)
S20 = 1140
Sum of the 20th terms is 1140
Answer:ceo
Step-by-step explanation:
Ceo
B, y goes up 8, when you add 8 to y