Answer: -1.5
Step-by-step explanation:
When population standard deviation is known, then the formula to find the z-test statistic for population mean is given by :-

, where n= Sample size.
= Population mean
= Sample mean
= Population standard deviation.
As per given , we have
(average infants contracted typhoid each month)

n= 4 (No. of months)
Then , the value of the appropriate test statistic will be :




Hence, the value of the test statistic = -1.5
Well since it gives you 2 gas stations it wants you to compare prices
Als gas station will be A
At-one will be B
since station A has $3.259/ gallon I assume
and B has $3.199/ gallon
just subtract them
so 3.259 -3.199 = 0.06
gas is less at station B noticeably costs less so thats your first answer
for the next one if you bought gallon of gas at the cheaper station you'd be saving $0.06/gallon since we got the difference from subtracting them.
Collect like terms (x + 7x) + (-1 + 4 - 3)
Simplify
Answer: 8x
Answer:
x = 13
Step-by-step explanation:
call the missing number x
8 - x = - 5 Subtract 8 from both sides
8-8 - x = -5-8 Combine
-x = - 13 Multiply by -1
x = 13
the center square is 20 x 20 = 400
there are 4 12 x 20 areas
12*20 = 240*4 = 960
960+400 = 1360 square inches