Q 3.2.

Question

Many people believe that the distribution of IQ scores follows a “bell curve,” like the one shown in the margin. But is this really how such scores are distributed? The IQ scores of 60 fifth-grade students chosen at random from one school are shown below.

Describe what you see. Is the distribution bell-shaped?

Step-by-Step Solution

Verified

Answer

Yes, It is bell shaped.

1Step 1: Given information

Below are the IQ scores of 60 fifth-grade students chosen at random from one school.

145	139	126	122	125	130	96	110	118	118
101	142	134	124	112	109	134	113	81	113
123	94	100	136	109	131	117	110	127	124
106	124	115	133	116	102	127	117	109	137
117	90	103	114	139	101	122	105	97	89
102	108	110	128	114	112	114	102	82	101

2Step 2: Concept

Shape: The peak of the dot plot is at This means that during that season, the team's most common number of goals scored in games (known as the mode) was The United States women's soccer team scored between one and five goals in the majority of its games. The distribution, however, has a large tail to the right.

3Step 3: Explanation

Graph:

For the given distribution of IQ scores, a histogram could be constructed as follows:

The above-constructed histogram is bell-shaped. Thus, it implies that the distribution is approximately normal.

Q 2.4.

Q 3.1.

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Q 3.1.

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Q 4.1.

Draw a correct histogram to replace Billy’s graph of the word length data from Caution 2. Length12345678910111213Count115257578776831

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145	139	126	122	125	130	96	110	118	118
101	142	134	124	112	109	134	113	81	113
123	94	100	136	109	131	117	110	127	124
106	124	115	133	116	102	127	117	109	137
117	90	103	114	139	101	122	105	97	89
102	108	110	128	114	112	114	102	82	101

145	139	126	122	125	130	96	110	118	118
101	142	134	124	112	109	134	113	81	113
123	94	100	136	109	131	117	110	127	124
106	124	115	133	116	102	127	117	109	137
117	90	103	114	139	101	122	105	97	89
102	108	110	128	114	112	114	102	82	101

145	139	126	122	125	130	96	110	118	118
101	142	134	124	112	109	134	113	81	113
123	94	100	136	109	131	117	110	127	124
106	124	115	133	116	102	127	117	109	137
117	90	103	114	139	101	122	105	97	89
102	108	110	128	114	112	114	102	82	101