##### STA2023 STATISTICS

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Elementary Statistics
updated 4 years ago by josie003
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1

The table to the right lists probabilities for the corresponding numbers of girls in three births. What is the random​ variable, what are its possible​ values, and are its values​ numerical?

Number_of_girls P(x)
0 0.125
1 0.375
2 0.375
3 0.125

Answer.The random variable is​ x, which is the number of girls in three births. The possible values of x are​ 0, 1,​ 2, and 3. The values of the random value x are numerical.

2

Five males with a particular genetic disorder have one child each. The random variable x is the number of children among the five who inherit the genetic disorder. Determine whether the table describes a probability distribution. If it​ does, find the mean and standard deviation.

x P(x)
0 0.2373
1 0.3955
2 0.2637
3 0.0879
4 0.0146
5 0.0010

m=1.3

random variable x=1

3

ed is not particularly creative. He uses the pickup line​ "If I could rearrange the​ alphabet, I'd put U and I​ together." The random variable x is the number of girls Ted approaches before encountering one who reacts positively. Determine whether the table describes a probability distribution. If it​does, find its mean and standard deviation.

x P(x)
1 0.002
2 0.033
3 0.138
4 0.216
5 0.402

The table is not a probability distribution.

4

Let the random variable x represent the number of girls in a family with three children. Assume the probability of a child being a girl is 0.47. The table on the right describes the probability of having x number of girls. Determine whether the table describes a probability distribution. If it​ does, find the mean and standard deviation. Is it unusual for a family of three children to consist of three​girls?

x P(x)
0 0.149
1 0.396
2 0.351
3 0.104