Answer:
2, 4.5 and 8
Step-by-step explanation:
(1)
The mode is the number which occurs most often , then
mode = 2
(2)
The median is the middle value of the numbers arranged in ascending order. If there is no exact middle value then it is the average of the numbers either side of the middle.
1, 2, 2, 3, 4, 5, 6, 7, 8, 9
↑ middle
median = =
= 4.5
(3)
The range is the difference between the largest and smallest values
range = 9 - 1 = 8
Answer:
A score of 150.25 is necessary to reach the 75th percentile.
Step-by-step explanation:
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.
A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30.
This means that
What score is necessary to reach the 75th percentile?
This is X when Z has a pvalue of 0.75, so X when Z = 0.675.
A score of 150.25 is necessary to reach the 75th percentile.