Pre – Assessment Test:
B
A
B
D
A
B
C
A
B
A
B
B
C
D

Explanation:

The median score is also the 5th decile since 1 decile is equivalent to 10 which makes 5th decile to be equal to 50 and the median of 100 is also 50.

When a distribution is divided into hundred equal parts, each score point that describes the distribution is called a percentile.

The lower quartile is equal to the 25th percentile.

Rochelle’s score is not below the 5th decile since 55 is greater than 50.

The median of 14, 17, 10, 22, 19, 24, 8, 12, and 19 is equivalent to 17 since 17 lies between all the scores when arranged in either descending or ascending order. Descending Order: 24, 22, 19, 19, 17, 14, 12, 10, 8. Ascending Order: 8, 10, 12, 14, 17, 19, 19, 22, 24.

Melody’s score is higher than 25% of her classmates.

If the 1st quartile of the ages of 250 fourth year students is 16 years old then 25% of the students are 16 years old.

If the passing mark of a 100 - item test is the 3rd quartile then the students should answer at least 75 items correctly to pass the exam.

Rachel’s score is 38 which belong to the upper quartile of the 50 – item test.

Given that the score distribution of 15 students is 83 72 87 79 82 77 80 73 86 81 79 82 79 74 74 then it follows that seven students scored higher than 79.

To solve for the 60th percentile of 40-45 |6 |18 |100.00 35-39 |5 |12| 66.67 30-34 |3 | 7 | 38.89 25-29 |4 |4 |22.22, the lower boundary must be equal to 34.5.

To solve for the 35th percentile of 40-45 |6 |18 |100.00 35-39 |5 |12| 66.67 30-34 |3 | 7 | 38.89 25-29 |4 |4 |22.22, the cumulative frequency must be equal to 7.

The 45th percentile of 40-45 |6 |18 |100.00 35-39 |5 |12| 66.67 30-34 |3 | 7 | 38.89 25-29 |4 |4 |22.22 is equal to 30.8.

The 50th percentile of 40-45 |6 |18 |100.00 35-39 |5 |12| 66.67 30-34 |3 | 7 | 38.89 25-29 |4 |4 |22.22 is equal to 37.5.

Formulas:

Median: For even number of terms: median = two middle terms/2

For odd number of terms: median = no. of terms + 1
/2

Examples:

Find the median of: 7, 9, 12, 13, and 16.

12

Find the median of $1.79, $1.61, $1.96, $2.09, $1.84, $1.75, $1. 80, and $2.11.

$1. 82

Solution: $1. 80 + $1. 84/2 = $3.64/2 = $1. 82

Percentile: R [100 (N + 1)]

Where: R is Percentile Rank,

P is Percentile,

N is The Number of Items

Percentile Rank: R = P / 100 (N + 1)

R is Percentile Rank,
P is Percentile,
N is The Number of Items

Quartile: To find the quartiles of a data:

Order the data from least to greatest.
Find the median of the data set and divide the data set into halves.
Find the median of the two halves.

Definition of Median:

Finding Percentile:

Finding Quartile: