Helen practiced the piano 5 days last week. The list below shows the number of minutes she practiced each day: 20,25,30,20,30 What is the MAD (mean absolute deviation) in Helen's practice times?

4

Step-by-step explanation:

Given the data:

X : 20,25,30,20,30

Mean absolute deviation :

Σ(x - xbar) / n

n = sample size = 5

xbar = ΣX / n = (20+25+30+20+30) /5

xbar = 25

((20-25) + (25-25) + (30-25) + (20-25) + (30-25)) / 5

We take the absolute values, hence, negative signs are ignored :

(5 + 0 + 5 + 5 + 5) / 5

20 / 5

= 4

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a

so the possibilities of the measurement of the side of the triangle are either it is longest side or not the longest side

when it is the longest side

s < 25 + 35s < 60

if it is not the longest side

35 < 25 + s10 < sso 10 < s < 60so the perimeter70 < p < 130