An article reported that for a sample of 40 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 165.23.
calculate and interpret a 95% (two-sided) confidence interval for true average co2 level in the population of all homes from which the sample was selected. (round your answers to two decimal places.)
= ppm
(b) suppose the investigators had made a rough guess of 167 for the value of s before collecting data. what sample size would be necessary to obtain an interval width of 57ppm for a confidence level of 95%? (round your answer up to the nearest whole number.)
= kitchens

 (a)  (602.95,705.37)

(b) 33

Step-by-step explanation:

(a) Given : Sample size :

Sample mean :

Standard deviation :

Significance level :

Critical value :

The confidence interval for population mean is given by :-

Hence, the 95% (two-sided) confidence interval for true average level in the population of all homes from which the sample was selected.

(b) Given : Standard deviation :

Margin of error :

Significance level :

Critical value :

The formula to calculate the sample size is given by :-

Hence, the minimum required sample size would be 33.

intensity of the vector is v= √37 ≈ 6.08 units and make angle ∡α ≈ 9.46° with east direction

step-by-step explanation:

required vector is consists of the two componentsvx= 2+4=6 units   and vy= 1 unit and vx ⊥ vywe will use pythagorian theorem to find intensity of the vector vv∧2 = vx∧2 + vy∧2 => v = √vx∧2 + vy∧2 = √6∧2 + 1∧2 = √36+1 = √37 ≈ 6.08 unitsthe angle ∡α between vector and east direction we wil find with tanαtanα = 1/6 => α = arc tanα = arc 1/6 => α ≈ 9.46°

hope this

because they could drop even lower..