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Unformatted text preview: Student: Grady Sinlonton Colu'se: Mathll9: Elementary Statistics  Spring 3010  CRN: 49339
Instructor: Shawn Pan'ini  16 weeks
Date: 31810 Book: T1'iola: Elementary Statistics. 11e Time: 11:01 AM Refer to the accompanying data set and use the 25 home voltage measurements to construct a frequency distribution
with ﬁve classes. Begin with a lower class limit of 131.3 volts, and use a class width of0.20 volt. Does the result appear
to have a normal distribution? Why or why not? @ Click the icon to view the data. To construct a frequency distribution. ﬁrst ﬁnd the lower class limits. To ﬁnd the lower class limits, add the class width
to the preceding lower class limit, starting with the given ﬁrst lower class limit. The ﬁrst lower class limit is 131.3, and the class width is 0.2. Determine the second lower class limit.
131.3 +0.2= 131.5 Add 0.2 to the second lower class limit to determine the third lower class limit.
131.5 +0.2= 131.7 The ﬁve lower class limits are shown below. 131.3
131.5
131.?
131.9
132.1 To ﬁnd the upper class limits, use the lower class limits to determine the largest numbers that can belong to the different
classes. Be sure the classes do not overlap. The ﬁrst upper class limit is the largest number that does not belong to the second class, which has a lower limit of
131.5. To determine the largest number that does not belong to the second class, subtract 0.] from the second lower class
limit. 131.50.1=l31.4 The ﬁve classes are shown below. 13131314
l31.5131.6
BITE131.8
13191321)
132.1132.2 To find the frequencies, take each individual data value and put a tally mark in the appropriate class, then add the tally
marks to ﬁnd the total frequency for each class. Complete the frequency distribution by tallying the frequencies for each class. The completed frequency distribution is
shown below. Page 1 Student: Grady Silnonton
Instructor: Shawn Panini Date: 3."'18.."'10
Voltage (volts)
131.3 131.4
131.5 131.6
131.7 131.8
131.9 132.0
132.1 132.2 Frequency 3
5
10
4
3 Course: Mathll9: Elelnentaiy Statistics  Spring 2010  C‘RN: 49239
 16 weeks Book: Triola: Elelnentaiy Statistics. Me Time: 11:01 AM Data that have an approximately normal distribution are characterized by a frequency distribution that starts low,
increases to one or two high frequencies, then decreases to a low frequency. Also, the frequencies are relatively
symmetric about the maximum frequency. Notice that the frequencies start at 3, then increase to 10, then decrease to 3. The class 131.7  131.8 has the highest
frequency and the distribution is approximately symmetric about this maximum. Use this information to determine if the frequency distribution appears to have a normal distribution. More Info Voltage Measurements From a Home 1 ﬁlial.thme Home Home Home Home
Day (volts) Day (volts) Day (volts) Day (volts) 131.9 8 131.8 15 131.9 22 131.6 131.8 9 131.9 16 131.8 23 131.5 131.4 10 131.? 1'? 131.8 24 131.? 132.1 11 131.4 18 131.5 25 131.5 132.1 12 131.?r 19 132.1 131.9 13 131.6 20 131.8 131.8 14 131.4 21 131.8 Page 2 ...
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 Spring '10
 PARVINI

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