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What percentage of the rats navigated the maze in less than 5.5 minutes?
Here again is the histogram showing the distribution of times, in minutes, required for 25 rats in an animal behavior experiment to navigate a maze successfully.
For the data described by the above histogram,
Here again is the histogram showing the distribution of times, in minutes, required for 25 rats in an animal behavior experiment to navigate a maze successfully.
A possible value of the median in this example is:
Here again is the histogram showing the distribution of times, in minutes, required for 25 rats in an animal behavior experiment to navigate a maze successfully.
Assume that the largest observation in this dataset is 8.6 minutes. If this observation were wrongly recorded as 86, then:
ANSWER:
84%
Good job! From the histogram we can find that 3 + 8 + 6 + 4 = 21 out of the 25 rats fall below 5.5 minutes (first four bars). Since the question asks about the percentage of observations, the answer is 21/25 * 100 = 84%
Q2
This information is not provided by the histogram
Q3
Which of the following best describes the shape of the histogram?
Q4
For the data described by the above histogram,
Good job! The mean is more sensitive than the median to the tail of a distribution, and also to outliers. We see that this distribution is skewed to the right (the tail is towards the right) and we also see a suspected outlier on the right side. Both of these shape features will tend to pull the mean more than they would pull the median. Therefore, in this case: mean > median.
Q5
A possible value of the median in this example is:
This is Correct.
There are n=25 observations in the data and therefore the median is the 13 th ranked observation. Note from the histogram that the 13 th observation falls in the third time interval (from the left) which is [3.5, 4.5) and therefore the median could be any number in this interval. The only possible answer in that interval is 3.9.
Q6
Assume that the largest observation in this dataset is 8.6 minutes. If this observation were wrongly recorded as 86, then:
Good job! The mean will increase, because the mean tends to be pulled by an outlier. So moving the largest value, 8.6, farther to the right, to 86, would tend to pull the mean to the right, making it larger. The median wouldn't be affected, because moving 8.8 to 86 wouldn't change the 13th value in the data.
he following 6 questions relate to the same histogram, shown below.