Module 1
Practise questions
1) The following data set lists the prices for thirty houses in and around Boston,
Massachusetts. Create a histogram of the data using the bins provided
in column D.
The Input Range is B1:B31 and the Bin Range is D1:D8. You must check
the Labels in first row box since we included B1 and D1 to ensure that the
histogram’s axes are appropriately labeled.
2) How would you describe the shape of the distribution shown below of the real
estate pricing data?
Uniform
A uniform distribution has constant probability across a range of possible outcomes.
Thus the bars of the histogram of a uniform distribution will have the same frequency
provided the bins over the range of possible outcomes are of equal size. Since the
frequencies of the bins in this graph vary, the distribution is not uniform.
Right-tailed
correct
,This graph has a tail that extends out the right side. As selling price increases, the
frequency of each bin above $600,000 is much less than those below $600,000.
Therefore, we infer that this distribution is skewed to the right, or right-tailed.
Left-tailed
This graph is not left-tailed. Although it has a tail, the tail extends out the right side, not
the left side. Thus we cannot infer that the distribution is left-tailed.
Symmetric
This graph is not symmetric; it has a tail that extends out to one side.
3) How many houses cost more than $400 thousand and less than or equal to $800
thousand?
Approximately 2
By convention, Excel includes in a bin’s range the number represented by the bin label.
For example, the first bin (labeled $200,000) includes all houses with values less than or
equal to $200,000 and the second bin (labeled $400,000) includes all houses with
values greater than $200,000 but less than or equal to $400,000. The only bins with
frequency 2 are the fourth bin (labeled $800,000), which indicates that approximately 2
houses cost more than $600,000 and less than or equal to $800,000, and the sixth bin
(labeled $1,200,000), which indicates that approximately 2 houses cost more than
, $1,000,000 and less than or equal to $1,200,000). The number of houses that cost more
than $400,000 and less than or equal to $800,000 is indicated by the height of the bars
at bins $600,000 and $800,000. How many houses cost more than $400,000 and less
than or equal to $800,000?
Approximately 11
correct
The number of houses that cost more than $400,000 and less than or equal to $800,000
is indicated by the height of the bars at bins $600,000 and $800,000. The frequency of
the bar above bin $600,000 is approximately 9 and the frequency of the bar above bin
$800,000 is approximately 2. Therefore, approximately 9+2=11 houses cost more than
$400,000 and less than or equal to $800,000.
Approximately 15
By convention, Excel includes in a bin’s range the number represented by the bin label.
For example, the first bin (labeled $200,000) includes all houses with values less than or
equal to $200,000 and the second bin (labeled $400,000) includes all houses with
values greater than $200,000 but less than or equal to $400,000. Approximately 15
houses cost less than or equal to $400,000. The number of houses that cost more than
$400,000 and less than or equal to $800,000 is indicated by the height of the bars at
bins $600,000 and $800,000. How many houses cost more than $400,000 and less than
or equal to $800,000?
Approximately 25
By convention, Excel includes in a bin’s range the number represented by the bin label.
For example, the first bin (labeled $200,000) includes all houses with values less than or
equal to $200,000 and the second bin (labeled $400,000) includes all houses with
values greater than $200,000 but less than or equal to $400,000. Approximately 25
houses cost less than or equal to $600,000. The number of houses that cost more than
$400,000 and less than or equal to $800,000 is indicated by the height of the bars at
bins $600,000 and $800,000 How many houses cost more than $400,000 and less than
or equal to $800,000?