Answer:
The percentage of students who scored below 620 is 93.32%.
Step-by-step explanation:
Problems of normally distributed samples are 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 question, we have that:

Percentage of students who scored below 620:
This is the pvalue of Z when X = 620. So



has a pvalue of 0.9332
The percentage of students who scored below 620 is 93.32%.
Look at the picture.
1)|AM| = |MB| = x
|AN| = |NC| = y
|BC| = 2y - 2x = 2(y - x)
|MN| = y - x
Therefore |BC| = 2|MN|
2)|AM| = |MB| = x
|AN| = |NC| = y
|BC| = 2y - 2x = 2(y - x)
|MN| = y - x
Therefore |BC| = 2|MN|
Answer:
option (b) df = 1, 24
Step-by-step explanation:
Data provided in the question:
levels of factor A, a = 2
levels of factor B, b = 3
Subjects in each Sample, s = 5
n = 5 × 3 × 2 = 30
Now
df for Factor A = a - 1
= 2 - 1
= 1
df for Factor B = b - 1
= 3 - 1
= 2
df for Interaction AB = ( a - 1 ) × ( b - 1 )
= 1 × 2
= 2
df for Total = n - 1
= 30 - 1
= 29
df for error = 29 - 5
= 24
Hence,
df values for the F-ratio evaluating the main effect of factor A is 1, 24
The correct answer is option (b) df = 1, 24