The following data points are the number of games pitched by each of the Greenbury Goblins' starting pitchers last season.

3,2,4,7

Find the standard deviation of the data set.

Round your answer to the nearest hundredth.

Can you please check what I did so far and help me out with the rest?

Thank you!

Answer:

4

Work:

(3+2+4+7)/4

=16/4

=4

Answer:

-1 | -2 | 0 | 3 |

Work:

3 | 2 | 4 | 7 |

3 - 4 | 2 - 4 | 4 - 4 | 7 - 4 |

-1 | -2 | 0 | 3 |

Then I'm stuck... 😭😭😭

Would LOVE some help out here... 🙂🙂🙂

\(Tommarvoloriddle\)

tommarvoloriddle Aug 19, 2019

edited by
tommarvoloriddle
Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

#1**+4 **

Sorry the edit keeps messing it up...

The first "answer" I put Mean on top of, so the mean is 4

the 2nd "answer" I put Difference things on top of.

The charts are the difference thingys...

But from there I have absolutely NO IDEA what to do...

😭 | 😭 | 😭 |

😭 | 😭 | 😭 |

😭 | 😭 | 😭 |

tommarvoloriddle Aug 19, 2019

edited by
tommarvoloriddle
Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

edited by tommarvoloriddle Aug 19, 2019

#2**+2 **

3,2,4,7

Find the standard deviation of the data set.

Round your answer to the nearest hundredth.

Standard deviation of the sample

\(s^2=\frac{\sum(x_i-\overline x)^2}{n-1}\)

\(n=4\\ \overline x=4\)

\(s^2=\frac{(3-4)^2+(2-4)^2+(4-4)^2+(7-4)^2}{4-1}\\ s^2=\frac{1+4+0+9}{3}\\ s^2=\frac{14}{3}\)

\(s=\sqrt{\frac{14}{3}}\\ s=2.1602469\)

\(s\approx 2.16\)

!

Guest Aug 19, 2019

#3**+2 **

3,2,4,7

Find the standard deviation of the data set.

Round your answer to the nearest hundredth.

Standard deviation of the sample

\(s^2=\frac{\sum (x_i-\overline x)^2}{n-1}\)

\(n=4\\ \overline x=\frac{3+2+4+7}{4}\\ \overline x=4\)

\(s^2=\frac{(3-4)^2+(2-4)^2+(4-4)^2+(7-4)^2}{4-1}\\ s^2=\frac{1+4+0+9}{3}\\ s^2=\frac{14}{3}\\ s=\sqrt{\frac{14}{3}}=2.1602469\)

\(s\approx 2.16\)

Standard deviation of the population

\(s^2=\frac{\sum (x_i-\overline x)^2}{n}\)

\(s^2=\frac{(3-4)^2+(2-4)^2+(4-4)^2+(7-4)^2}{4}\\ s^2=\frac{1+4+0+9}{4}\\ s^2=\frac{14}{4}\\ s=\sqrt{\frac{14}{4}}=1.87083\)

\(s\approx 1.87\)

!

asinus Aug 19, 2019

#6**+5 **

I didn't know there was a formula...

Thank you for your answers!

But I think your way is the better way, as my math textbook is just teaching you steps you can use but are crazily bulky.

tommarvoloriddle
Aug 19, 2019

#5**+5 **

I learned it using steps like above but you would continue it like this(found my math textbook yay)

:

x | mean | x-mean | (x-mean)^2 |

3 | 4 | -1 | 1 |

2 | 4 | -2 | 4 |

4 | 4 | 0 | 0 |

7 | 4 | 3 | 9 |

I knew this | I knew this | I knew this | I figured it out right now |

Then you have to find the mean of the last column

(1+4+0+9)/4

14/4

7/2

then square root that to get

sqrt(7/2)

and the answers sqrt(7/2)

which is around 1.87

(Textbook way, no formula...)

I think This problem was categorized terribly as it accepts the population answer.

tommarvoloriddle Aug 19, 2019