1, The following table contains the number of successes and failures for three categories of a variable. Test whether the proportions are equal for each category at the α=0.01 level of significance.
_ Category_1 Category_2 Category_3
Failures 69 31 33
Successes 81 32 77
What is the P-value?
(Round to three decimal places as needed.)
What conclusion can be made?
A.The P-value is greater than or equal to α, so reject H0. There is sufficient evidence that the categories of the variable and success and failure are dependent.
B.The P-value is less than α, so reject H0. There is not sufficient evidence that the categories of the variable and success and failure are dependent.
C.The P-value is less than α, so not reject H0. There is sufficient evidence that the proportions are different from each other.Your answer is not correct.
D.The P-value is greater than or equal than α, so do not reject H0. There is not sufficient evidence that the proportions are different from each other.
The following data represent the level of health
and the level of education for a random sample of 1812 residents. Complete parts (a) and (b) below. |
Education | Excellent | Good | Fair | Poor |
Not a H.S. graduate | 125 | 206 | 94 | 145 |
H.S. graduate | 69 | 175 | 72 | 95 |
Some college | 85 | 177 | 84 | 113 |
Bachelor Degree or higher | 74 | 148 | 51 | 99 |
Calculate the test statistic.
whats the P-value
In: Statistics and Probability
Suppose that in a simple random sample of 100 people, 69 of them believe the Seahawks will win the Superbowl this year. We want to determine if the proportion of people in the population who believes this is less than 0.75.
Choose the appropriate concluding statement.
a. The sample data do not provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is less than 0.75.
b. The sample data provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is less than 0.75.
c. The sample data do not provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is less than 0.69.
d. The sample data provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is less than 0.69.
e. The sample data do not provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is greater than or equal to 0.75.
f. The sample data provide evidence that the proportion of people who believe the Seahawks will win the SuperBowl is greater than or equal to 0.75.
In: Statistics and Probability
Resuelva cada uno de los ejercicios de pruebas NO paramétricas:
Se han seleccionado aleatoriamente una muestra de 82 estudiantes de Instituto y otra con 46
estudiantes de centros privados y se ha considerado la nota en Educación Física para cada uno
de ellos. Los datos obtenidos vienen resumidos en la siguiente tabla de contingencia.
Insuf | Suf o bien | notable | sobresaliente | total | |
Centro Privado (private center) | 7 | 14 | 17 | 9 | 47 |
Instituto
Institute |
30 | 32 | 17 | 3 | 82 |
37 | 46 | 34 | 12 | 129 |
tipo de centro de Enseñanza
English sample of 82 Institute students was randomly selected and another with 46 students from private schools and the note in Physical Education has been considered for each from them. The data obtained are summarized in the following contingency table.
Use the above table
We wish to contrast the hypothesis that the distribution of grades in Physical Education is independent of the type of teaching center
In: Statistics and Probability
Resuelva cada uno de los ejercicios de pruebas NO paramétricas:
1. La efectividad de la publicidad para dos productos rivales (Marcas X e Y) fueron comparadas. Se hizo una investigación de mercado en un centro comercial local, donde a los participantes se les muestra un aviso publicitario de entre dos productos rivales de marcas de café, los cuales ellos evaluarán en una escala del 1 (definitivamente NO compraré el producto) al 10 (definitivamente SI compraré el producto). A la mitad de los participantes se les mostró el aviso publicitario de un producto mientras que a la otra mitad el del otro producto. Los datos obtenidos son los siguientes:
Brand X | Brand Y | |||
Participant | Rating | Participant | Rating | |
1 | 3 | 1 | 9 | |
2 | 4 | 2 | 7 | |
3 | 2 | 3 | 5 | |
4 | 6 | 4 | 10 | |
5 | 2 | 5 | 6 | |
6 | 5 | 6 | 8 |
Aplique una prueba de hipótesis para determinar si ambas marcas tienen la misma aceptación. En caso de no ser así indique que marca es más aceptada. Arroje conclusiones. Calcule el estadístico de prueba. Grafique (Graph) la región de rechazo. Calcule el valor p de la prueba (p-value).
English
Solve each of the non-parametric test exercises: 1. The effectiveness of advertising for two rival products (Trademarks X and Y) were compared. A market research was conducted at a local shopping center, where participants are shown an advertisement from two rival coffee brand products, which they will evaluate on a scale of 1 (I will definitely NOT buy the product) at 10 (I will definitely buy the product). Half of the participants were shown the advertising of one product while the other half of the other product. The data obtained are the following:
use data above
Apply a hypothesis test to determine if both brands have the same acceptance. If not, indicate which brand is more accepted. Throw conclusions. Calculate the test statistic. Graph (Graph) the rejection region. Calculate the p-value of the test (p-value).
In: Statistics and Probability
A local brewery sells their beer in 330 ml bottles. On average
the beer is filled with 328.1 ml with a standard deviation of 0.9
ml. Since it is possible to under-fill the bottle but impossible to
fill the bottle with more than 330 ml, the distribution is skewed
left. Use this information and Excel functions to answer the
following questions, and round your answers to four decimal
places.
a. What is the probability that the average fill of a six-pack will
be greater than 328.5 ml?
b. What is the probability that the average fill of a twelve-pack
will be greater than 328.5 ml?
c. What is the probability that the average fill of a twelve-pack
will be less than 327.8 ml
In: Statistics and Probability
Resuelva cada uno de los ejercicios de pruebas NO paramétricas:
Una agencia publicitaria está investigando a qué tipo de avisos le prestan más atención los
adolescentes. Se observan a 11 niños, a 6 se les muestra avisos sobre comida y a los 5 restantes
se les muestra avisos sobre bebidas. Todos los avisos tienen duración similar. Se registra el
tiempo de atención (en segundos) de los 11 niños.
Los datos se resumen a continuación:
Tipo aviso/ Notice type |
B |
C |
B |
B |
B |
B |
C |
C |
C |
C |
C |
Datos Ordenados/ Ordered Data |
23 |
25 |
28 |
30 |
35 |
38 |
41 |
42 |
45 |
47 |
50 |
English
An advertising agency is investigating what kind of ads pay more attention to teenagers. 11 children are observed, 6 are shown notices about food and the remaining 5 They are shown warnings about drinks. All notices have a similar duration. The registration is recorded attention time (in seconds) of the 11 children. The data is summarized above: Apply a non-parametric test to determine if there are statistically significant differences between both groups. If there are, tell which is the group of notices to which the children pay more attention. Show the whole procedure. Calculate the statistic, and draw conclusions.
In: Statistics and Probability
Calculate the five-number summary of the given data. 11 7 2 17 18 2 13 22 16 1 20 21 20 23 24
In: Statistics and Probability
Specify sample spaces for the random experiments (a)-(e) and give mathematical descriptions of the corresponding events. (a) Experiment: A coin is tossed three times. Event: The result of the second toss is “heads”. (b) Experiment: Three indistinguishable coins are tossed at the same time. Event: At most two of the coins show “heads”. (c) Experiment: A die is rolled until each number has appeared at least once. The outcome is the number of rolls needed. Event: Less than 15 rolls are needed. (d) Experiment: n devices labeled with 1, . . . , n are inspected. It is of interest which devices are working and which are not. Event: The first three devices are defective. (e) Experiment: n devices are inspected. Interest lies in the number of defective devices. Event: Exactly three devices are defective.
In: Statistics and Probability
Difference between Means, Sample size selection.
Explain Confidence Interval for a Mean, Total, Proportion, Standard Deviation.
Methods of Selecting Random Samples.
In: Statistics and Probability
In a random sample of
8
people, the mean commute time to work was
35.5
minutes and the standard deviation was
7.3
minutes. A
98%
confidence interval using the t-distribution was calculated to be
left parenthesis 27.8 comma 43.2 right parenthesis(27.8,43.2).
After researching commute times to work, it was found that the population standard deviation is
8.7
minutes. Find the margin of error and construct a
98%
confidence interval using the standard normal distribution with the appropriate calculations for a standard deviation that is known. Compare the results.
In: Statistics and Probability
Suppose we have a binomial experiment in which success is defined to be a particular quality or attribute that interests us.
(a) Suppose n = 43 and p = 0.36.
(For each answer, enter a number. Use 2 decimal places.)
n·p =
n·q =
Can we approximate p̂ by a normal distribution? Why? (Fill
in the blank. There are four answer blanks. A blank is represented
by _____.)
_____, p̂ _____ be approximated by a normal random
variable because _____ _____.
first blank
Yes or No
second blank
can or cannot
third blank
n·p exceeds
n·p and n·q do not exceed
n·q exceeds
n·p does not exceed
n·q does not exceed
both n·p and n·q exceed
fourth blank (Enter an exact number.)
__________
What are the values of μp̂ and
σp̂? (For each answer, enter a number.
Use 3 decimal places.)
μp̂ =
σp̂ =
(b) Suppose n = 25 and p = 0.15.
Can we safely approximate p̂ by a normal distribution?
Why or why not? (Fill in the blank. There are four answer blanks. A
blank is represented by _____.)
_____, p̂ _____ be approximated by a normal random
variable because _____ _____.
first blank
Yes or No
second blank
can or cannot
third blank
n·p exceeds
n·p and n·q do not exceed
n·q exceeds
n·p does not exceed
n·q does not exceed
both n·p and n·q exceed
fourth blank (Enter an exact number.)
_____
(c) Suppose n = 56 and p = 0.19.
(For each answer, enter a number. Use 2 decimal places.)
n·p =
n·q =
Can we approximate p̂ by a normal distribution? Why? (Fill
in the blank. There are four answer blanks. A blank is represented
by _____.)
_____, p̂ _____ be approximated by a normal random
variable because _____ _____.
first blank
Yes or No
second blank
can or cannot
third blank
n·p exceeds
n·p and n·q do not exceed
n·q exceeds
n·p does not exceed
n·q does not exceed
both n·p and n·q exceed
fourth blank (Enter an exact number.)
_____
What are the values of μp̂ and
σp̂? (For each answer, enter a number.
Use 3 decimal places.)
μp̂ =
σp̂ =
In: Statistics and Probability
The speeds of car traveling on Interstate Highway I-35
are normally distributed with a mean of 74
miles per hour and a standard deviation of 6 miles per hour.
(a) Find the percentage of the cars traveling on this highway with
a speed
i. of more than 85,
ii. between 65 to 72.
(b) If a BMW is at the speed that is faster than 90 percentage of
cars, what is the speed of the
BMW?
In: Statistics and Probability
Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for Vanguard Total Stock Index (all stocks). Let y be a random variable representing annual return for Vanguard Balanced Index (60% stock and 40% bond). For the past several years, we have the following data.
x: |
19 |
0 |
34 |
15 |
13 |
20 |
37 |
−23 |
−17 |
−17 |
y: |
17 |
−4 |
25 |
18 |
12 |
23 |
12 |
−5 |
−8 |
−10 |
(a) Compute Σx, Σx2, Σy, Σy2.
Σx | Σx2 | ||
Σy | Σy2 |
(b) Use the results of part (a) to compute the sample mean,
variance, and standard deviation for x and for y.
(Round your answers to two decimal places.)
x | y | |
x | ||
s2 | ||
s |
(c) Compute a 75% Chebyshev interval around the mean for x
values and also for y values. (Round your answers to two
decimal places.)
x | y | |
Lower Limit | ||
Upper Limit |
Use the intervals to compare the two funds.
a. 75% of the returns for the balanced fund fall within a narrower range than those of the stock fund.
b. 75% of the returns for the stock fund fall within a narrower range than those of the balanced fund.
c. 25% of the returns for the balanced fund fall within a narrower range than those of the stock fund.
d. 25% of the returns for the stock fund fall within a wider range than those of the balanced fund.
(d) Compute the coefficient of variation for each fund. (Round your
answers to the nearest whole number.)
x | y | |
CV | % | % |
Use the coefficients of variation to compare the two funds.
a. For each unit of return, the stock fund has lower risk.
b. For each unit of return, the balanced fund has lower risk.
c. For each unit of return, the funds have equal risk.
If s represents risks and x represents expected
return, then s/x can be thought of as a measure
of risk per unit of expected return. In this case, why is a smaller
CV better? Explain.
a. A smaller CV is better because it indicates a higher risk per unit of expected return.
b. A smaller CV is better because it indicates a lower risk per unit of expected return.
In: Statistics and Probability
4. You have collected weekly earnings and age data from a sub-sample of 1,744 individuals using the Current Population Survey in a given year.
(a) Given the overall mean of $434.49 and a standard deviation of $294.67, construct a 99% confidence interval for average earnings in the entire population. State the meaning of this interval in words, rather than just in numbers. If you constructed a 90% confidence interval instead, would it be smaller or larger? What is the intuition?
(b) When dividing your sample into people 45 years and older, and younger than 45, the information shown in the table is found.
Age Category |
Average Earnings |
Standard Deviation |
N |
Age ≥ 45 |
$468.87 |
$308.64 |
507 |
Age < 45 |
$412.20 |
$276.63 |
1237 |
Test whether or not the difference in average earnings is statistically significant. Given your knowledge of age-earning profiles, does this result make sense?
In: Statistics and Probability
Let X~BIN(40,0.1). Let Y=max(0,x-3). FindE[Y].
In: Statistics and Probability