An article reported that for a sample of 46 kitchens with gas cooking appliances monitored during a one-week period, the sample mean CO2 level (ppm) was 654.16, and the sample standard deviation was 163.7. Required:
a. Calculate and interpret a 9596 (two-sided) confidence interval for true average CO2 level in the population of all homes from which the sample was selected.
b. Suppose the investigators had made a rough guess of 175 for the value of s before collecting data. What sample size would be necessary to obtain an interval width of 50 ppm for a confidence level of 95%?

a) CI = ( 148,69 ; 243,31 )

b) n = 189

Step-by-step explanation:

a)  If the Confidence Interval is 95 %

α = 5 %     or   α = 0,05     and   α/2  = 0,025

citical value for α/2  =  0,025     is    z(c) = 1,96

the  MOE   ( margin of error is )  

1,96* s/√n

1,96* 163,7/ √46

MOE =  47,31

Then  CI  =  196 ± 47,31

CI = ( 148,69 ; 243,31 )

CI look very wide ( it sems that if sample size was too low )

b) Now if s (sample standard deviation) is 175, and we would like to have only 50 ppm width with Confidence  level 95 %, we need to make

MOE = 25 = z(c) *  s/√n

25*√n = z(c)* 175

√n   =  1,96*175/25

√n  = 13,72

n = 188,23

as n is an integer number we make n = 189

answer: idk

step-by-step explanation:

so firstly, we need to isolate the y variables to be able to solve these inequalities. firstly, add 0.5x on both sides of the first inequality and subtract 1.5x on both sides of the second inequality:

now since the slope is positive for the first inequality, this means that the line going upwards belongs to the first inequality, and the line going downwards belongs to the second inequality.

next, since y ≥ in the first inequality, this means that the shaded region will be above the first inequality's line, thus shading regions a and b.

next, since y ≤ in the second inequality, this means that the shaded region is going to be below this line, thus shading regions a and c.

since both lines shade region a, this means that region a is the solution.

step-by-step explanation:

mark brainliest!