I have four different sweaters. Every day I choose one of the four sweaters at random to wear. Let X be the number of different sweaters I wore during a 5-day week.

(For example, if my 5-day sweater sequence is 3,2,4,4,2 then X = 3 because that week I wore sweaters {2,3.4}.)


Find the mean of X.

Respuesta :

Answer:

Mean is 6

Step-by-step explanation:

Mean refers to the average of the observations.

Let X be the number of different sweaters I wore during a 5-day week.

Possible values of X = 1, 2, 3, 4

For X = 1, [tex]P(X=1)=\frac{1}{5}[/tex]

For X = 2, [tex]P(X=2)=\frac{2}{5}[/tex]

For X = 3, [tex]P(X=3)=\frac{3}{5}[/tex]

For X = 4, [tex]P(X=4)=\frac{4}{5}[/tex]

To find: Mean

Solution:

[tex]\sum_{x=1}^{4}xP(X=x)=1P(X=1)+2P(X=2)+3P(X=3)+4P(X=4)\\=1\left ( \frac{1}{5} \right )+2\left ( \frac{2}{5} \right )+3\left ( \frac{3}{5} \right )+4\left ( \frac{4}{5} \right )\\=\frac{1}{5}+\frac{4}{5}+\frac{9}{5}+\frac{16}{5}\\=\frac{1+4+9+16}{5}\\=\frac{30}{5}\\=6[/tex]

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