Question

Ello.

Grade 9, Statistics.

The class mark of a class interval is 30. If the class size is 10, find the upper limit and the lower limit of the class.

20pts.

Answer 1

Answer:

25,35

Step-by-step explanation:

Given, Class mark of a class interval (a) = 30.

Given, Class size (h) = 10.

∴ Lower limit = a - h/2

                     = 30 - (10/2)

                     = 30 - 5

                     = 25.

∴ Upper limit = a + (h/2)

                      = 30 + (10/2)

                      = 30 + 5

                      = 35.

Therefore:

⇒ Upper limit of the class = 25.

⇒ Lower limit of the class = 35.

∴ Class interval = 25 - 35.

Hope it helps!

Answer 2

hey!

•class mark is the midpoint of a class interval

it is founded by upper + lower limit /2

•class size - difference b/w upper and lower limit

______________________________

let lower limit be x

then upper limit be x+10

class mark = upper + lower limit /2

30= x+10+x/2

60 = 2x+10

50/2=x

x=25

•lower limit is 25

•upper limit is 25+10=35