The depth d centimeters of a river was recorded each day during a period of one year (365 days) when the frequency curve
300
frequency 200
100
ie
20
30
40
SO
60
70
depth, d (cm)
(a) Use the cumulative frequency curve to find
the median depth
(i) the inter-quartile range.
(1) the depth at the 40 percentile,
(iv) the number of days when the depth of the river was at least 25 cm.

For a science project, a high school research team conducted a survey of local air temperatures. based on the results of the survey, the found that the average temperatures were around 10 degrees higher than expected. this result was wrong. the trouble with the survey was that most of the locations were exposed to direct sunlight and located over asphalt or sand, which resulted in higher temperatures than normal. this is a classic example of an error in which phase of inferential statistics?