Sample size= n= 84
sample mean= x = 107 s
population standard deviation =σ= 11.7

As, population standard deviation is given so we use the estimate:
x(+/-) z(α/2)(σ/√n)

At 99% Confidence interval means significance level is α=1-0.99= 0.01
So,
α/2=0.005
Now, z at α/2=0.005
z= 2.576
Now, by putting values
107(+/-)((2.576)(11.7/√84))
( 107-((2.576)(11.7/√84)), 107+((2.576)(11.7/√84)) )
(103.7, 110.288)

4 0

4 years ago

PLEASE HELP ME I NEED TO DO THIS TGA

tigry1 [53]

Step-by-step explanation:

a) -2 - (-9) = 7

→ -2 + 9 = 7

as, when the bracket will be open ( - ) (-) = + so 9 will be positive and as 2 is negative they will get subtracted and as 9 is greater no. and have a positive sign so, the answer will be positive as well.

b) -2-9 = -11

as the both numbers are negative so they will get added so we got 11 and also they bith share negative sign so in addition or subtraction the result will have the same sign as the numbers which are added have.

c) -2 - (-9) - (-2) = 9

→ -2 + 9 + 2

→ -2 + 11 = 9

when both the bracket will get open so the negative sign will change with positive so 2 and 9 have a positive sign and as they have similar sign when they will get add up than they will have same sign so we will get 9+2=11, a positive 11 and as 2 is negative so they will be subtracted and 11 is greater so we will have a positive 9.

hope this answer helps you dear...and may u have a great day ahead!

6 0

3 years ago