Question

In R studio please explain

how to do the stemplot?

A sample of 20 endangered species was obtained and the length of time (in months) since being placed on the list was recorded for each species. A stemplot of these data follows. In the stemplot, 5|2 represents 52 months.

5   2 4 8 9 9

6   0 0 3 5 6 7 8 9

7   3 4 7 8 9 9

8

9   8

The median length of time (in months) since being placed on the list for these 20 species is:

a) 66.0.

b) 66.5.

c) 67.0.

d) 67.5.

In measuring the center of the data from a skewed distribution, the median would be preferred over the mean for most purposes

because:

a) the median is the most frequent number while the mean is most likely

b) the mean may be too heavily influenced by the larger observations and this gives too high an indication of the center

c) the median is less than the mean and smaller numbers are always appropriate for the center

d) the mean measures the spread in the data

e) the median measures the arithmetic average of the data excluding outliers.

The ratio level of measurement is represented in which variable below?

a) Zip code

b) Class standing (freshman, sophomore, junior, senior

c) High temperature

d) Age

Consider the basic syntax of the barplot function .

barplot(H, xlab, ylab, main, names.arg, col, border) Then names.arg

a) is a vector of the labels to be used for the x-axis and y-axis.

b) is a vector containing numeric values used in bar chart.

c) is a vector of the names that will appear under each bar

d) is used to define the title of the bar chart

An R tibble displays:

a) only the first 10 rows, and all the columns that fit on screen.

b) only the first 10 rows and the first 10 columns

c) all rows and all columns

d) all rows and all the columns that fit on screen

Answer 1

We have given the A sample of 20 endangered species was obtained and the length of time (in months) since being placed on the list was recorded for each species. A stem plot of these data follows.

In the stem plot, 5|2 represents 52 months.

5   2 4 8 9 9

6   0 0 3 5 6 7 8 9

7   3 4 7 8 9 9

8

9   

the numbers is as 52,54,58,59,59, 60,60,63,65,66,67,68,69 ,73,74,77,78,79,79

we have to calculate the median length of time (in months) since being placed on the list for these 20 species is:

We Know that formula for the Median is  

If the total number of numbers(n) is an even number, then the formula is given below:

if the given number is in ascending order

n=20

In R code is as

x<-c(52,54,58,59,59, 60,60,63,65,66,67,68,69 ,73,74,77,78,79,79)

median(x)

R -Output

66

therefore here

Median=66.

Option A is correct.

• Result: median length of time (in months) since being placed on the list for these 20 species is: 66

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In measuring the center of the data from a skewed distribution, the median would be preferred over the mean for most purposes

• for option A the mode is is the most frequent number while the mean is most likely. so Option A is wrong.
• for the option B   we know that the Median is the most Robust i.e. the median is appropriate in the presence of outliers. and the presence of outliers the mean is violated to the large number therefore the Option B is correct .i.e. the mean may be too heavily influenced by the larger observations and this gives too high an indication of the center
• For option C there is no need that Median is smaller than mean. Option C is wrong.
• For option D. The dispersion statistics measures the variation in the data and Median is the not the dispersion statistics it is the one of the measures of central tendency. Option D is wrong.
• For option E. The median measures the arithmetic average of the data excluding outliers. Option E is wrong.

• Result: In measuring the center of the data from a skewed distribution, the median would be preferred over the mean for most purposes: B) the mean may be too heavily influenced by the larger observations and this gives too high an indication of the center.

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we have to find out the The ratio level of measurement is represented in which variable below

Variable	Scale
Zip code	Nominal Scale
Class standing (freshman, sophomore, junior, senior	Ordinal Scale
High temperature	Interval Scale
Age	ratio Scale

• Result: The ratio level of measurement is represented in D) Age

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syntax of the barplot function is as

barplot(H, xlab, ylab, main, names.arg, col, border) Then names.arg

a) is a vector of the labels to be used for the x-axis and y-axis.

Option A is wrong. xlab and the ylab arguments are used for the labels to be used for the x-axis and y-axis.

b) is a vector containing numeric values used in bar chart.

Option B is wrong. above syntax H will a vector containing numeric values used in bar chart

c) is a vector of the names that will appear under each bar

Option C is correct. The Syntax names.arg is used for the names that will appear under each bar

d) is used to define the title of the bar chart

Option D is wrong. title argument are used for the define the title of the bar chart.

• Result: Then names.arg Option C is correct. The Syntax names.arg is used for the names that will appear under each bar

____________________________________________________________________________________________

An R tibble displays:

a) only the first 10 rows, and all the columns that fit on screen.

Option A is correct.

b) only the first 10 rows and the first 10 columns

c) all rows and all columns

d) all rows and all the columns that fit on screen

• Result:  An R tibble displays: A) only the first 10 rows, and all the columns that fit on screen.

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