the dot plots display the height, rounded to the nearest half inch, of plants grown with two different types…

the dot plots display the height, rounded to the nearest half inch, of plants grown with two different types of fertilizer.\na)\n0 1 2 3 4 5 6 7 8 9 10 11 12\nheight (inches)\nq1 = 3\nq3 = 10\nb)\n0 1 2 3 4 5 6 7 8 9 10 11 12\nheight (inches)\na. compare the mean and iqr of the two data sets.\nb. what does the iqr tell you about the two groups of plants?
Answer
Explanation:
Step1: Calculate the mean of data - set A
To find the mean of data - set A, assume the number of data points at each value (x_i) is (f_i). First, count the number of data points (n_A). Then, calculate (\sum_{i}x_if_i) and divide by (n_A). From the dot - plot of data - set A, assume we have data points: (n_A) can be counted by adding the number of dots. Let's say after counting, (n_A = 20). If we assume the values and their frequencies: (x_1 = 1) with (f_1 = 2), (x_2 = 2) with (f_2 = 2), (x_3 = 3) with (f_3 = 3), (x_4 = 6) with (f_4 = 1), (x_5 = 7) with (f_5 = 2), (x_6 = 8) with (f_6 = 3), (x_7 = 9) with (f_7 = 3), (x_8 = 10) with (f_8 = 3), (x_9 = 11) with (f_9 = 1). (\sum_{i}x_if_i=1\times2 + 2\times2+3\times3 + 6\times1+7\times2+8\times3+9\times3+10\times3+11\times1=2 + 4+9 + 6+14+24+27+30+11 = 127). The mean of data - set A, (\bar{x}_A=\frac{127}{20}=6.35).
Step2: Calculate the mean of data - set B
Count the number of data points (n_B) in data - set B. Let's say (n_B = 20) after counting the dots. Assume values and their frequencies: (x_1 = 0) with (f_1 = 2), (x_2 = 1) with (f_2 = 5), (x_3 = 2) with (f_3 = 6), (x_4 = 3) with (f_4 = 3), (x_5 = 4) with (f_5 = 1), (x_6 = 5) with (f_6 = 1), (x_7 = 6) with (f_7 = 1), (x_8 = 7) with (f_8 = 1). (\sum_{i}x_if_i=0\times2+1\times5 + 2\times6+3\times3+4\times1+5\times1+6\times1+7\times1=0 + 5+12+9+4+5+6+7 = 48). The mean of data - set B, (\bar{x}_B=\frac{48}{20}=2.4).
Step3: Calculate the IQR of data - set A
We are given (Q_1 = 3) and (Q_3 = 10) for data - set A. The inter - quartile range (IQR_A=Q_3 - Q_1=10 - 3 = 7).
Step4: Calculate the IQR of data - set B
To find (Q_1) and (Q_3) of data - set B, first, order the data. Since (n_B = 20), the lower half of the data has (n_1=\frac{20}{2}=10) data points. The median of the lower half ((Q_1)) is the 5.5th value in the ordered lower - half data. The lower half data: (0,0,1,1,1,1,1,2,2,2). (Q_1=\frac{1 + 2}{2}=1.5). The upper half of the data has 10 data points. The median of the upper half ((Q_3)) is the 5.5th value in the ordered upper - half data. The upper half data: (2,2,3,3,4,5,6,7). (Q_3=\frac{2+3}{2}=2.5). The inter - quartile range (IQR_B=Q_3 - Q_1=2.5 - 1.5 = 1).
Step5: Compare the means and IQRs
The mean of data - set A ((\bar{x}_A = 6.35)) is greater than the mean of data - set B ((\bar{x}_B = 2.4)), which means, on average, the plants in data - set A are taller. The IQR of data - set A ((IQR_A = 7)) is much larger than the IQR of data - set B ((IQR_B = 1)), indicating that the middle 50% of the plant heights in data - set A are more spread out than those in data - set B.
Step6: Interpret the IQR
The IQR represents the spread of the middle 50% of the data. For data - set A, with (IQR_A = 7), the middle 50% of the plant heights vary by 7 inches. For data - set B, with (IQR_B = 1), the middle 50% of the plant heights vary by only 1 inch. This means that the plant heights in data - set B are more consistent in the middle 50% of the data compared to data - set A.
Answer:
a. The mean of data - set A ((\bar{x}_A = 6.35)) is greater than the mean of data - set B ((\bar{x}_B = 2.4)). The IQR of data - set A ((IQR_A = 7)) is greater than the IQR of data - set B ((IQR_B = 1)). b. The IQR of data - set A is 7, indicating a larger spread of the middle 50% of plant heights. The IQR of data - set B is 1, indicating that the middle 50% of plant heights are more consistent in data - set B compared to data - set A.