Question

How many observations should be included sample if we wish X to be within 0.2 ounce of u with probability 0.90​

Answer 1

Answer:

The line in the table on which they begin (you may want to specify one if the text does not). ... For the numbers 1, 2, 3, 4, for example, we would have ... 1.46 For measurements in ounces, divide x and s by 28.35.

Answer 2

Given:

ounce : 0.2

probability P = 0.90​

To find:

no of observations n =?

Explanation:

• Now we need  

P(|Y¯ − µ| ≤ 0.2) = P(−2 ≤ Y¯ − µ ≤ 0.2) = 0.90.

• Divide each term of the inequality by σY¯ = 1√n, we get

P(−0.2√n ≤ Z ≤ 0.2√n) = 0.90

where Z ∼ N (0, 1).

• By using a probability table, we have to find

P(−1.91 ≤ Z ≤ 1.91) = 0.90.

• It must follow that 0.2√n = 1.91 or,

equivalently,

$\displaystyle n= \frac{1.91^2}{0.2^2}$

   = 85.5

n ≅ 85

The no of observations required is 85.