Alonzo and Cheryl are both members of a population, and a simple random sample is being conducted. If the chance of Alonzo being selected is [tex]\frac{1}{200n}[/tex], what is the chance of Cheryl being selected?

A. [tex]\frac{1}{290}[/tex]
B. [tex]\frac{1}{2900}[/tex]
C. [tex]\frac{1}{29,000}[/tex]
D. [tex]\frac{1}{29}[/tex]



Answer :

In a simple random sample, each individual member of the population has an equal probability of being selected. This means that if Alonzo has a certain probability of being selected, Cheryl should have the same probability, given that they are both members of the same population.

Given that the chance of Alonzo being selected is [tex]\( \frac{1}{200n} \)[/tex], let's denote this probability as [tex]\( P(\text{Alonzo}) \)[/tex].

Since the probability for Cheryl should be the same in a simple random sample, we can write:
[tex]\[ P(\text{Cheryl}) = \frac{1}{200n} \][/tex]

Next, we need to compare this probability with the options provided:

A. [tex]\( \frac{1}{290} \)[/tex]

B. [tex]\( \frac{1}{2900} \)[/tex]

C. [tex]\( \frac{1}{29,000} \)[/tex]

D. [tex]\( \frac{1}{29} \)[/tex]

Clearly, we need to find which of these options matches [tex]\( \frac{1}{200n} \)[/tex]. Let's examine each option one by one:

1. Option A: [tex]\( \frac{1}{290} \)[/tex]

2. Option B: [tex]\( \frac{1}{2900} \)[/tex]

3. Option C: [tex]\( \frac{1}{29,000} \)[/tex]

4. Option D: [tex]\( \frac{1}{29} \)[/tex]

To determine the matching probability, we need to identify how [tex]\( \frac{1}{200n} \)[/tex] can fit one of these forms.

For [tex]\( \frac{1}{200n} \)[/tex] to match any of these options, the denominator [tex]\( 200n \)[/tex] must be equal to 290, 2900, 29,000, or 29 for some value of [tex]\( n \)[/tex].

We check the given fractions:

- If [tex]\( \frac{1}{200n} = \frac{1}{290} \)[/tex], then [tex]\( 200n = 290 \)[/tex], so [tex]\( n = \frac{290}{200} = 1.45 \)[/tex]. This is not a typical integer value for [tex]\( n \)[/tex].

- If [tex]\( \frac{1}{200n} = \frac{1}{2900} \)[/tex], then [tex]\( 200n = 2900 \)[/tex], so [tex]\( n = \frac{2900}{200} = 14.5 \)[/tex]. Again, this is not a typical integer value for [tex]\( n \)[/tex].

- If [tex]\( \frac{1}{200n} = \frac{1}{29000} \)[/tex], then [tex]\( 200n = 29000 \)[/tex], so [tex]\( n = \frac{29000}{200} = 145 \)[/tex]. This is a reasonable integer value for [tex]\( n \)[/tex].

- If [tex]\( \frac{1}{200n} = \frac{1}{29} \)[/tex], then [tex]\( 200n = 29 \)[/tex], so [tex]\( n = \frac{29}{200} = 0.145 \)[/tex]. This is a very impractically small number for [tex]\( n \)[/tex].

Therefore, [tex]\( \frac{1}{29000} = \frac{1}{200n} \)[/tex] works with [tex]\( n = 145 \)[/tex].

Hence, the chance of Cheryl being selected is [tex]\( \frac{1}{29000} \)[/tex]. The correct answer is:

C. [tex]\( \frac{1}{29,000} \)[/tex]