Curva normal
Páginas: 4 (776 palabras)
Publicado: 30 de noviembre de 2011
Tu Nombre: Nadia Pérez, Alejandra Rubio, Miriam Gutiérrez, María Fernanda Limón
The Normal Distribution: Homework
Exercise 2
IQ is normally distributed with a mean of 100 and a standard deviationof 15. Suppose one individual is randomly chosen. Let X = IQ of an individual.
a. X N( 100 , +/- 15 ) X=(120-100)/15= 1.3333=90.824%
b. Find the probability that the person has an IQgreater than 120.
Include a sketch of the graph and
write a probability statement.
X=(120-100)/15= 1.3333=90.824%
9.176%
El IQ 120 se encuentra a 1.333 desviaciones estándar de la media normal,según las tablas de área bajo la curva corresponde al 90.824% por lo que existe una probabilidad del 9.176% de que la persona tenga un IQ arriba de 120.
c. Mensa is an organization whose members havethe top 2% of all IQs. Find the minimum IQ needed to qualify for the Mensa organization.
Sketch the graph and
write the probability statement.
i) 2.06=(N-100)/15
ii)(2.06*15)+100=N -N=130.9
2%
El 2% de la curva normal corresponde a IQ’s más altos que 130.09, éste valor corresponde a la puntuación Z=2.06, es decir 2 desviaciones estándar de la media. El áreacoloreada corresponde al 2% de coeficientes intelectuales que caen más arriba de 130.
d. The middle 50% of IQs fall between what two values?
Sketch the graph and
write the probability statement.i) N=(0.68*15)+100=110.2
ii) N=(-0.67*15)+100=89.95
50%
Z=0.68=75.175%
IQ=110.2
Z=-0.67=25.143%
IQ=89.95
Exercise 3
The percent of fat calories that a person in Americaconsumes each day is normally distributed with a mean of about 36 and a standard deviation of 10. Suppose that one individual is randomly chosen.
Let X = percent of fat calories.
a. X N( 36,+/-10 )
b. Find the probability that the percent of fat calories a person consumes is more than 40. Graph the situation. Shade in the area to be determined.
i) Z=(40-36)/10=0.4...
The Normal Distribution: Homework
Exercise 2
IQ is normally distributed with a mean of 100 and a standard deviationof 15. Suppose one individual is randomly chosen. Let X = IQ of an individual.
a. X N( 100 , +/- 15 ) X=(120-100)/15= 1.3333=90.824%
b. Find the probability that the person has an IQgreater than 120.
Include a sketch of the graph and
write a probability statement.
X=(120-100)/15= 1.3333=90.824%
9.176%
El IQ 120 se encuentra a 1.333 desviaciones estándar de la media normal,según las tablas de área bajo la curva corresponde al 90.824% por lo que existe una probabilidad del 9.176% de que la persona tenga un IQ arriba de 120.
c. Mensa is an organization whose members havethe top 2% of all IQs. Find the minimum IQ needed to qualify for the Mensa organization.
Sketch the graph and
write the probability statement.
i) 2.06=(N-100)/15
ii)(2.06*15)+100=N -N=130.9
2%
El 2% de la curva normal corresponde a IQ’s más altos que 130.09, éste valor corresponde a la puntuación Z=2.06, es decir 2 desviaciones estándar de la media. El áreacoloreada corresponde al 2% de coeficientes intelectuales que caen más arriba de 130.
d. The middle 50% of IQs fall between what two values?
Sketch the graph and
write the probability statement.i) N=(0.68*15)+100=110.2
ii) N=(-0.67*15)+100=89.95
50%
Z=0.68=75.175%
IQ=110.2
Z=-0.67=25.143%
IQ=89.95
Exercise 3
The percent of fat calories that a person in Americaconsumes each day is normally distributed with a mean of about 36 and a standard deviation of 10. Suppose that one individual is randomly chosen.
Let X = percent of fat calories.
a. X N( 36,+/-10 )
b. Find the probability that the percent of fat calories a person consumes is more than 40. Graph the situation. Shade in the area to be determined.
i) Z=(40-36)/10=0.4...
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