Question

A pair of surfers collected data on the self-reported numbers of days surfed in a month for 30 longboard surfers and 30 shortboard surfers. Complete parts a and b below.

Longboard: 2, 7, 16, 13, 10, 18, 7, 8, 15, 15, 19, 17, 3, 10, 11, 16, 24 5, 20, 6, 9, 11, 8, 21, 22, 18, 14, 12, 16, 24
Shortboard: 17, 16, 7, 5, 13, 8, 7, 6, 15, 8, 8, 16, 10, 23, 24, 10, 20, 16, 16, 24, 23, 14, 6, 12, 10, 7, 12, 25, 13, 22
a) Compare the typical number of days surfing for these two groups.
The median for the longboards was________ days, and the median for the shortboards was_______ days, showing that those with________ typically surfed more days in this month
b) Compare the interquartile ranges.
The interquartile range for the longboards was________ days, and the interquartile range for the shortboards was_______ days, showing more variation in the days surfed this month for the________

Answer 1

(a)The median for the longboards was 13.5 days, and the median for the shortboards was 13 days, showing that those with longboards typically surfed more days in this month.

(b)The interquartile range for the longboards was 10 days, and the interquartile range for the shortboards was 10.5 days, showing more variation in the days surfed this month for the shortboards.

Explanation:

Longboard:

2, 7, 16, 13, 10, 18, 7, 8, 15, 15, 19, 17, 3, 10, 11, 16, 24 5, 20, 6, 9, 11, 8, 21, 22, 18, 14, 12, 16, 24

Sorting in ascending order, we have:

`2, 3, 5, 6, 7, 7, \boxed{8, 8}, 9, 10, 10, 11, 11, 12, \boxed{13, 14,} 15,15, 16, 16, 16, 17, \boxed{18, 18}, 19, 20, 21, 22, 24 , 24`

Median
`=(13+14)/(2)=13.5`

`Q_1=(8+8)/(2)=8 \\Q_3=(18+18)/(2)=18\\$Interquartile range, Q_3-Q_1=18-8=10`

Shortboard

17, 16, 7, 5, 13, 8, 7, 6, 15, 8, 8, 16, 10, 23, 24, 10, 20, 16, 16, 24, 23, 14, 6, 12, 10, 7, 12, 25, 13, 22

Sorting in ascending order, we have:

`5, 6, 6, 7, 7, 7, \boxed{8, 8,} 8, 10, 10, 10, 12, 12, \boxed{13, 13} 14, 15, 16, 16, 16, 16, \boxed{17, 20,} 22, 23, 23, 24, 24, 25`

Median
`=(13+13)/(2)=13`

`Q_1=(8+8)/(2)=8 \\Q_3=(17+20)/(2)=18.5\\$Interquartile range, Q_3-Q_1=18.5-8=10.5`

Therefore:

(a)The median for the longboards was 13.5 days, and the median for the shortboards was 13 days, showing that those with longboards typically surfed more days in this month.

(b)The interquartile range for the longboards was 10 days, and the interquartile range for the shortboards was 10.5 days, showing more variation in the days surfed this month for the shortboards.