Transcript File

Chapter 6: Normal Distribution
Review
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LAST MAN STANDING
MILDLY
SOMEWHAT
TOTALLY
COSTUMED
MAN
Round
Of
Applause
Piece of
Gum
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WEIRD
MAN
Candy
Candy
High Five
ANGRY
MAN
Extra
Credit Pt
Fist Bump
Piece of
Gum
Mrs. Green’s daughter is weighed at
the pediatrician and compared to all
other babies that are the same age.
The doctor gives her weight with a
z-score of 0.71. What percent of all
babies are HEAVIER than Mrs
Green’s baby?
.2389 or 23.89%
The number of pieces of
candy kids get on
halloween is normally
distributed with a mean of
35 pieces of candy and a
standard deviation of 8.4.
What percent of kids will
get less than 20 pieces of
candy?
.0367 or 3.67%
The amount of water that a high
school student drinks during the day
is normally distributed with a mean
of 2.25L and a standard deviation of
1.3 L. What percent of students
drink between 2 and 3 liters of
water each day?
Z-Scores: -0.19 & 0.58
Percentages: 0.4247 & 0.7190
Answer: .2943 or 29.43%
In a Normal Distribution
with a mean of 15 and a
standard deviation of 4.1,
what z-scores would
represent the most extreme
8%?
Z < -1.75 or Z > 1.75
On a college chemistry exam, the scores are
normally distributed with a mean of 74 and a
standard deviation of 9.5. The professor has
decided that the middle 40% of the scores
will receive a C. Between what two scores is
the range for a C?
Answer: 69.06 < x < 78.94
NO CALCULATOR!!
After polling a group of 8th graders, it was
determined that the amount of sleep they got each
night was a normal distribution with parameters
N(7.8, 1.1). What percent of students got less than
6.7 hours of sleep?
Draw the 68-95-99.7 Rule!!
Answer: 100 – 68 = 32 32/2 = 16%
Blood tests often detect potential
problems by measuring different
components in your blood. These
measurements are compared to normal
measurements to determine if a problem
exists. In one study of glucose levels, a
mean of 89.3 and standard deviation of
6.2 was observed in study participant.
What glucose level would be more
alarming, a reading of 105 or a reading of
75.2?
Z-score of 105: 2.53
Z-score of 75.2: -2.27
While both are very far from
the mean, the reading of 105
would be more concerning.
An ELL teacher is trying to identify students who
have become proficient enough in English to be
phased out of the program. Each year they take a
test that is normally distributed with the following
parameters: N(85, 7.2). She feels that the top 10%
of students would be considered proficient. What
test score would a student have to get to be
considered proficient?
-0.7 < z < 0.7
Percentiles: 0.2420 & 0.7580
Answer: 0.516 or 51.6%