3.1

13 type answers

Mean=(34+33.2+37+29.4+23.6+25.9)/6 =30.52 Median=(29.4+33.2)/2=29.80 Mode: none

14 type answers

Mean=(60.5+128.0+84.6+122.3+78.9+94.7+85.9+89.9)/8=93.10 Median=(85.9+89.9)/2=87.9 Mode: none

15 type answers

Mean=(3960+4090+3200+3100+2940+3830+4090+4040+3780)/9=3670
Median=3960
Mode: none

16 type answers

Mean: (282+270+260+257+260+267)/7=228
Median=266
Mode=260

17

  1. type answer

    The mean is larger than median, because the few larger values on the right part of the histogram make the mean larger. On the contrary, median is just the number in the meddle which is less likely to be influenced by really large numbers.

  2. type answer

    The mean is approximately equal to the median, because this is a bell-shaped curve.

  3. type answer

    The mean is smaller than median, because it is a left skewed curve and the small values make the mean smaller.

3.2

5 type answer

sample mean=(20+13+4+8+10)/5=11 sample variance=((20-11)2+(13-11)2+(4-11)2+(8-11)2+(10-11)^2)/(5-1)=36 sample standard deviation=6

6 type answer

sample mean=82 sample variance=100 sample standard deviation=10

7 type answer

population mean=9 population variance=16 population standard deviation=4

8 type answer

population mean=15 population variance=64 population standard deviation=8

9 type answer

sample mean=30 sample variance=196 sample standard deviation=14

10 type answer

population mean=12 population variance=30 population standard deviation=5.48

14 type answer

range=282-257=25 sample standard deviation=8.43

24

  1. 6 seconds

68% of eruptions last between 97.89 and 110.39

95% of eruptions last between 92 and 116 seconds, because sample mean+2s=116, sample mean-2s=92.

Actual percentage of eruptions that last between 92 and 116 seconds=(44-42)/44=95.45%

18% of eruptions last less than 98 seconds.

Actual percentage of eruptions that last less than 98 seconds=4/44=9.09%