7/25/2019 Descriptive Statistics (biostat)

1/2

!"#"$%"$&% ()* +,#*-#&./"$ !&$.1&.% "#$%$' ()* +,,-. "#/0. 1&2'#/ +3$45 +. 65$-/

DESCRIPTIVE STATISTICS

Measures of Central Tendency

Mean: ! !!

!

or ! !!

!

Median: the middle observation

Mode: the observation(s) which occurred most

frequently

Measures of Other LocationQuartiles (Q1, Q2, Q3, Q4)

Deciles (D1, D2, D3, D4, , D10)

Percentiles (P1, P2, P3, P4, , P100)

Measures of Variability / DispersionRange

Interquartile Range (IQR)

Mean Absolute Deviation (MAD)

Variance

Standard Deviation

Coefficient of Variation (CV) /

Relative Standard Deviation (RSD)

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Examples:

Word Problem 1: Breaking force of seven randomly selected ibuprofen tablets were measured using 8Mtablet hardness tester. Breaking force is the resistance of the tablet against the applied force until it breaks.

Results are as follows (in kP):

11.6 14.1 9.7 10.0 10.8 10.0 10.8

Compute for the following:

1. Mean

2. Median

3. Mode

4. 1stQuartile

5. 3rd

Decile

6. 75thPercentile

7. Range

8. Interquartile Range

9. Variance

10.Standard Deviation

11.Coefficient of

Variation

7/25/2019 Descriptive Statistics (biostat)

2/2

!"#"$%"$&% ()* +,#*-#&./"$ !&$.1&.% "#$%$' ()* +,,-. "#/0. 1&2'#/ +3$45 +.

Word Problem 2: USP disintegration time of six randomly selected tablets with breaking force

of 10 kP were gathered. Results (in sec) are as follows:

27 40 36 41 40 26

Compute for the following:

1. Mean

2. Median

3.

Mode

4. 3rd

Quartile

5. 7thDecile

6.

25thPercentile

7. Range

8. Interquartile Range

9. Variance

10.Standard Deviation

11.Relative Standard

Deviation

Word Problem 3:Cholesterol levels (in mg/dL) of all the residents of KatitingIsland were

recorded. Data are as follows: 61.3 62.4 69.1 64.1

68.3 65.3 66.0 71.5

Compute for the following:1. Mean

2. Median

3. Mode

4. 1stQuartile

5. 17thPercentile

6. Range

7. Interquartile Range

8. Variance

9. Standard Deviation

10.Coefficient of Variation