Step-by-step explanation:
Data values:
- 50- 1
- 57- 2
- 60- 4
- 65- 3
- 72- 3
- 75- 12
- 77- 10
- 81- 6
- 83- 6
- 88- 9
- 90- 12
- 92- 12
- 95- 2
- 99- 4
- 100- 5?
Question 1: What is the mean? The standard deviation?
The mean = the average = all of the data values added together and then divided by the number of data values.
The standard deviation= the average of the squared differences from the mean.
To find standard deviation:
- Find the mean
- For each data value (number), subtract the mean and square the difference (result)
Ex: You have 5 data values, 600, 470, 170, 430, and 300.
The mean of these data values is [tex]\frac{600+470+170+430+300}{5}[/tex]
- Then work out the average of those squared differences.
Mean calculations: All of the data values added together= 50+57+57+60+60+60+60+65+65+65+72+72+72+75+75+75+75+75+75+75+75+75+75+75+75+77+77+77+77+77+77+77+77+77+77+81+81+81+81+81+81+83+83+83+83+83+83+88+88+88+88+88+88+88+88+88+90+90+90+90+90+90+90+90+90+90+90+90+92+92+92+92+92+92+92+92+92+92+92+92+95+95+99+99+99+99+100+100+100+100+100=7531
Number of data values: 91
7531/91= 82.75824175 = 82.8
The mean is 82.8.
Standard deviation:
11.34347 (sample)
11.28097 (population)
Let's go with population because this appears to be all of the grades.
11.28097 is the standard deviation (population).
Part 2: Explain how to find the standard deviation.
1. Find the mean.
2. For each data value (number), subtract the mean and square the difference (result)
3. Find the mean of those differences.
Part 3: The data values are very spread out.
Hope this helps!
