Answer:
21
Step-by-step explanation:
Using<em> Simple Random Sampling</em>, we can estimate the sample size by the formula
where
n = sample size
Z = the z-score corresponding to the confidence level 99.5%
S = the assumed standard deviation = 3 seconds
e = margin of error = 2 seconds
<em>It is worth noticing that the higher the confidence level, the larger the sample should be.
</em>
The z-score corresponding to a confidence level of 99.5% can be obtained either with a table or the computer and equals
Z = 3.023
Replacing the values in our formula
So the size of the sample should be at least 21.
➻ In a group of 40 people, 27 can speak English and 25 can speak Spanish.
➻ The required number of people who can speak both English and Spanish .
<u>Consider</u> ,
➻ A → Set of people who speak English.
➻ B → Set of people who speak Spanish
➻ A∩B → Set of people who can speak both English and Spanish
➻ n(A∪B) = n(A) + n (B) - n(A∩B)
➻ 40 = 27 + 25 - n (A∩B)
➻ 40 = 52 - n (A∩B)
➻ n (A∩B) = 52 - 40
➻ ∴ n (A∩B) = 12
∴ Required Number of persons who can speak both English and Spanish are <u>12 .</u>
━━━━━━━━━━━━━━━━━━━━━━
➻ n(A∪B) = n(A) + n (B) - n(A∩B)
➻ 40 = 27 + 25 - 12
➻ 40 = 52 - 12
➻ 40 = 40
➻ ∴ L.H.S = R.H.S
━━━━━━━━━━━━━━━━━━━━━━
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Answer:
81.12 cm²
Step-by-step explanation:
The area for a semicircle can be figured with this formula: (πr²)/2. The triangle's area formula is bh/2.
(3.14 * 4²)/2 + (14 * 8)/2 <em>(Work the operations in parentheses first.)</em>
(3.14 * 16)/2 + 112/2
50.24/2 + 112/2 (<em>Divide 50.24 by 2. Do the same for 112.)</em>
25.12 + 56 (<em>Add 25.12 & 56.)</em>
81.12 cm²
The area of the figure is 81.12 cm².
Answer:
a = 16
Step-by-step explanation:
24:8 is the ratio
simplify into 3:8
6 ÷ 3 = 2
multiply the ratio by 2 to get a=16
