Mathematics: Mrs.douglas wanted to give each of her students 3 fancy pencils. she has 20 students. if fancy pencils come in packs of 12, how many packs does she need to purchase so that all of her students get their pencils?

Mrs.douglas wanted to give each of her students

Mynameismath

23.06.2021

Option D) $13.755 \pm 1.245$

Step-by-step explanation:

The table is attached in the question.

We are given the following in the question:

Population mean, μ = 15 hours per week

Sample mean = 13.755 hours per week

Degree of freedom = 25

Standard error = 0.707

Alpha, α = 0.05

First, we design the null and the alternate hypothesis

$H_{0}: \mu = 15\text{ hours per week}\\H_A: \mu \neq 15\text{ hours per week}$

95% confidence interval:

$\bar{x} \pm t_{critical}\text{Standard error}$

Putting the values, we get,

$t_{critical}\text{ at degree of freedom 25 and}~\alpha_{0.05} = \pm 1.761$

$13.755 \pm 1.761(0.707) = 13.755 \pm 1.245 = (1.9052 ,4.3952)$

Thus, the correct answer is

Option D) $13.755 \pm 1.245$

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