Question

entertai s mob oximate inmen latform eir fam of free y time Servings of fruit per day FIGURE 1.1 The dstrbuton of frt consumptnimple o74 rs for Exerose 1 30 scores of 78 seventh-grade students in a rural midwestern school. (a) Four students had low scores that might be considered 1Q test scores. Figure 1.15 is a stemplot of the 1Q test 1.31 ment outliers. Ignoring these, describe the shape, centet, and variability of the remainder of the distribution. nt tions are centered at 100. What percent of these 78 students have scores above 100? (b) We often read that IQ scores for large popula 7 2 4 7 79 8 8 69 9 01 33 9 6778 10 0022333 344 10 555666777789 11 00001 1 11 22223 3 3 4444 11 55688999 12 003 3 44 12 677888 13 02 13 6 d. or The dsriou scores for 78 seventh-grade students forDec 13 FIG

Answer 1

Sol:

Data from steam and leaf plot can be read as vector IQ in R.

IQ <- c(72,74,77,79,86,89,90,91,93,93,96,97,97,98,
100,100,102,102,103,103,103,103,104,104,
105,105,105,106,106,106,107,107,107,107,108,109,
110,110,110,110,111,111,111,111,112,112,112,112,
113,113,113,114,114,114,114,115,115,116,118,118,119,119,119,
120,120,123,123,124,124,126,127,127,128,128,128,
130,132,136)
fivenum(IQ)

the four outliers are 72,74,77,79

If we remove this

and plot histogram,Rcode is

IQ <- c(86,89,90,91,93,93,96,97,97,98,
100,100,102,102,103,103,103,103,104,104,
105,105,105,106,106,106,107,107,107,107,108,109,
110,110,110,110,111,111,111,111,112,112,112,112,
113,113,113,114,114,114,114,115,115,116,118,118,119,119,119,
120,120,123,123,124,124,126,127,127,128,128,128,
130,132,136)
hist(IQ)

mean(IQ)
sd(IQ)

From histogram we observe

distribution is normal

shape:symmetrical

center :mean=110.7297

spread:standard deviation= 10.86568

SolutionB:

the given below scores are above 100

102,102,103,103,103,103,104,104,
105,105,105,106,106,106,107,107,107,107,108,109,
110,110,110,110,111,111,111,111,112,112,112,112,
113,113,113,114,114,114,114,115,115,116,118,118,119,119,119,
120,120,123,123,124,124,126,127,127,128,128,128,
130,132,136

= 62/78*100

=0.7948718*100

=79.49%

79.49% of these 78 students have score above 100