Test 1: How to interpret different graphs

Question 1

How do you interpret a box and whisker plot and why would you do so?

Answer 1

-Smallest value is the minimum value.

-You would use with subgroup variable (e.g. grades of students that take a specific proffesor).

-Whiskers indicate variability outside the upper and lower quartiles.

-Upper quartile and lower quartile is median of their respective values. Lower is bottom 25% and upper is those in the top 75%

How to find first and third quartile
-Middle number of first half
-IQR is Q3-Q1

Lower outlier threshold: =Q1-(1.5)X(IQR)

Upper outlier threshold: = Q3+(1.5)X(IQR)

Question 2

When would you use a histogram?

Answer 2

-Use when data is numerical, looking to record frequency.

Question 3

When would you use a bar graph?

Answer 3

-You want to know the quantity, ratio and frequency of each category in a chart (e.g amount of deaths in different countries).

Question 4

How to calculate variance?

Answer 4

-Find the mean of the (μ) numbers given.

-Subtract the mean from each of the numbers (x), square the difference and find their sum.

-Divide the result by the total number of observations (N).