Help with Data Modeling Questions and Answers

UkusakazaL 2021-08-07

Determine whether each statement below is true or false
All data distributions are normally distributed.

OlmekinjP 2021-08-06

An alternative to the lognormal distribution for modeling highly skewed populations is the Pareto distribution with parameters θ and r. The probability density function is

Rivka Thorpe 2021-08-06

What are the data modeling concepts used in MongoDB? What are the main CRUD operations of MongoDB?

Ava-May Nelson 2021-08-06

What are the data modeling concepts used in column-based NOSQL systems and Hbase?

UkusakazaL 2021-08-06

In a normal distribution, a data value located 1 standard deviations below the mean has Standard Score: $z =$
In a normal distribution, a data value located 2.2 standard deviations above the mean has Standard Score: $z =$
In a normal distribution, the mean has Standard Score: $z =$

UkusakazaL 2021-08-05

Data such as "occupation" would use categorical frequency distributions:
True and False?

UkusakazaL 2021-08-04

Solve the following
If the join probability distribution of X and Y iss given by
$f (x, y) = \frac{x + y}{30}$
f or $x = 0, 2, 3 :$
$y = 0, 1, 2$
Find
a) $P (X \leq 2, Y = 1) .$
b) $P (X > 2, Y \leq 1) .$
c) $P (X > Y) .$

UkusakazaL 2021-08-04

a. Let $X \sim N (0, 1) and E \sim N (0, 1)$ be independent, and let $Y = X + β E$ . Show that $r_{x y} = \frac{1}{\sqrt{β^{2} + 1}}$ b.Use the results of part (a) to generate bivariate samples (x_i, y_i) of size 20 with population correlation coefficients −.9, −.5, 0, .5, and .9, and compute the sample correlation coefficients. c. Have a partner generate scatterplots as in part (b) and then guess the correlation coefficients.

slaggingV 2021-08-04

Calculate the amount that follows the given investment. $$ 700$ invested at $4 %$ compounded daily after a period of 4 years:
After 4 years, the investement results in how much $?

UkusakazaL 2021-08-03

Create equations to represent a relationship between quantities.
Define appropriate quantities for . . . descriptive modeling
Marcie can assemble 1 puzzle in 2 hours, and Janice can assemble 2 puzzles in 5 hours. How many hours will it take Marcie and Janice to assemble a puzzle if they work together?

UkusakazaL 2021-08-02

A club at school decided to help the homeless this year. Last month, the club got people to donate 879 blankets it can give to homeless people and families who need to stay warm. It gives about 150 blankets away each week. Write an equation modeling how many blankets it will have left over time.

UkusakazaL 2021-07-31

A privately owned liquor store operates both a drive-n facility and a walk-in facility. On a randomly selected day, let X and Y, respectively, be the proportions of the time that the drive-in and walk-in facilities are in use, and suppose that the joint density function of these variables is
$f (x, y) = {\begin{cases} \frac{2}{3} (x + 2 y) & 0 \leq x \leq 1, 0 \leq y \leq 1 \\ 0 & , e l s e w h e r e \end{cases}$
a) Find the marginal density of X.
b) Find the marginal density of Y.
c) Find the probability that the drive-in facility is busy less than one-half of the time.

necessaryh 2021-06-13

1. The standard error of the estimate is the same at all points along the regression line because we assumed that A. The observed values of y are normally distributed around each estimated value of y-hat. B. The variance of the distributions around each possible value of y-hat is the same. C. All available data were taken into account when the regression line was calculated. D. The regression line minimized the sum of the squared errors. E. None of the above.

arenceabigns 2021-06-10

Here’s an interesting challenge you can give to a friend. Hold a $1 (or larger!) bill by an upper corner. Have a friend prepare to pinch a lower corner, putting her fingers near but not touching the bill. Tell her to try to catch the bill when you drop it by simply closing her fingers. This seems like it should be easy, but it’s not. After she sees that you have released the bill, it will take her about 0.25 s to react and close her fingers-which is not fast enough to catch the bill. How much time does it take for the bill to fall beyond her grasp? The length of a bill is 16 cm.

Lennie Carroll 2021-06-09

The following table represents the Frequency Distribution and Cumulative Distributions for this data set: 12, 13, 17, 18, 18, 24, 26, 27, 27, 30, 30, 35, 37, 41, 42, 43, 44, 46, 53, 58

$\begin{array}{cc} Class & Frequency & Relative Frequency & Cumulative Frequency \\ 10 but les than 20 & 5 \\ 20 but les than 30 & 4 \\ 30 but les than 40 & 4 \\ 40 but les than 50 & 5 \\ 50 but les than 60 & 2 \\ TOTAL \end{array}$

What is the Relative Frequency for the class: 20 but less than 30? State you answer as a value with exactly two digits after the decimal. for example 0.30 or 0.35

midtlinjeg 2021-06-01

Let x be a continuous random variable with a standard normal distribution. Using the accompanying standard normal distribution table, find $P (x \geq 2.26)$

Emily-Jane Bray 2021-05-05

A random sample of $n_{1} = 14$ winter days in Denver gave a sample mean pollution index $x_{1} = 43$ .
Previous studies show that $σ_{1} = 19$ .
For Englewood (a suburb of Denver), a random sample of $n_{2} = 12$ winter days gave a sample mean pollution index of $x_{2} = 37$ .
Previous studies show that $σ_{2} = 13$ .
Assume the pollution index is normally distributed in both Englewood and Denver.
(a) State the null and alternate hypotheses.
$H_{0} : μ_{1} = μ_{2} . μ_{1} > μ_{2}$
$H_{0} : μ_{1} < μ_{2} . μ_{1} = μ_{2}$
$H_{0} : μ_{1} = μ_{2} . μ_{1} < μ_{2}$
$H_{0} : μ_{1} = μ_{2} . μ_{1} \neq μ_{2}$
(b) What sampling distribution will you use? What assumptions are you making?
The Student's t. We assume that both population distributions are approximately normal with known standard deviations.
The standard normal. We assume that both population distributions are approximately normal with unknown standard deviations.
The standard normal. We assume that both population distributions are approximately normal with known standard deviations.
The Student's t. We assume that both population distributions are approximately normal with unknown standard deviations.
(c) What is the value of the sample test statistic? Compute the corresponding z or t value as appropriate.
(Test the difference $μ_{1} - μ_{2}$ . Round your answer to two decimal places.)
(d) Find (or estimate) the P-value. (Round your answer to four decimal places.)
(e) Based on your answers in parts (i)−(iii), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level $α$ ?
At the $α = 0.01$ level, we fail to reject the null hypothesis and conclude the data are not statistically significant.
At the $α = 0.01$ level, we reject the null hypothesis and conclude the data are statistically significant.
At the $α = 0.01$ level, we fail to reject the null hypothesis and conclude the data are statistically significant.
At the $α = 0.01$ level, we reject the null hypothesis and conclude the data are not statistically significant.
(f) Interpret your conclusion in the context of the application.
Reject the null hypothesis, there is insufficient evidence that there is a difference in mean pollution index for Englewood and Denver.
Reject the null hypothesis, there is sufficient evidence that there is a difference in mean pollution index for Englewood and Denver.
Fail to reject the null hypothesis, there is insufficient evidence that there is a difference in mean pollution index for Englewood and Denver.
Fail to reject the null hypothesis, there is sufficient evidence that there is a difference in mean pollution index for Englewood and Denver. (g) Find a 99% confidence interval for
$μ_{1} - μ_{2}$ .
(Round your answers to two decimal places.)
lower limit
upper limit
(h) Explain the meaning of the confidence interval in the context of the problem.
Because the interval contains only positive numbers, this indicates that at the 99% confidence level, the mean population pollution index for Englewood is greater than that of Denver.
Because the interval contains both positive and negative numbers, this indicates that at the 99% confidence level, we can not say that the mean population pollution index for Englewood is different than that of Denver.
Because the interval contains both positive and negative numbers, this indicates that at the 99% confidence level, the mean population pollution index for Englewood is greater than that of Denver.
Because the interval contains only negative numbers, this indicates that at the 99% confidence level, the mean population pollution index for Englewood is less than that of Denver.

Joni Kenny 2021-03-18

a) To calculate: The least squares regression line for the data points using the table given below. $\begin{array}{cc} F e r t i l i z e r & x & 100 & 150 & 200 & 250 \\ Y i e l d & y & 35 & 44 & 50 & 56 \end{array}$ b)To calculate: The approximate yield when 175 pounds of fertizers were used per acre of land.

iohanetc 2021-03-11

Let's say the widget maker has developed the following table that shows the highest dollar price p. widget where you can sell N widgets. Number N Price p $200 53.00$
$250 52.50$
$300 52.00$
$35051.50$

(a) Find a formula for pin terms of N modeling the data in the table.

(b) Use a formula to express the total monthly revenue R, in dollars, of this manufacturer in month as a function of the number N of widgets produced in a month. $R =$ Is Ra linear function of N?

(c) On the basis of the tables in this exercise and using cost, $C = 35 N + 900$ , use a formula to express the monthly profit P, in dollars, of this manufacturer asa function of the number of widgets produced in a month $p =$ ?

Marvin Mccormick 2021-03-11

An automobile tire manufacturer collected the data in the table relating tire pressure x (in pounds per square inch) and mileage (in thousands of miles). A mathematical model for the data is given by
$ f (x) = - 0.554 x^{2} + 35.5 x - 514 .$
$\begin{array}{cc} x & M i l e a g e \\ 28 & 45 \\ 30 & 51 \\ 32 & 56 \\ 34 & 50 \\ 36 & 46 \end{array}$
(A) Complete the table below.
$\begin{array}{cc} x & M i l e a g e & f (x) \\ 28 & 45 \\ 30 & 51 \\ 32 & 56 \\ 34 & 50 \\ 36 & 46 \end{array}$
(Round to one decimal place as needed.)
$A . 20602060 x f (x)$
A coordinate system has a horizontal x-axis labeled from 20 to 60 in increments of 2 and a vertical y-axis labeled from 20 to 60 in increments of 2. Data points are plotted at (28,45), (30,51), (32,56), (34,50), and (36,46). A parabola opens downward and passes through the points (28,45.7), (30,52.4), (32,54.7), (34,52.6), and (36,46.0). All points are approximate.
$B . 20602060 x f (x)$
Acoordinate system has a horizontal x-axis labeled from 20 to 60 in increments of 2 and a vertical y-axis labeled from 20 to 60 in increments of 2.
Data points are plotted at (43,30), (45,36), (47,41), (49,35), and (51,31). A parabola opens downward and passes through the points (43,30.7), (45,37.4), (47,39.7), (49,37.6), and (51,31). All points are approximate.
$C . 20602060 x f (x)$
A coordinate system has a horizontal x-axis labeled from 20 to 60 in increments of 2 and a vertical y-axis labeled from 20 to 60 in increments of 2. Data points are plotted at (43,45), (45,51), (47,56), (49,50), and (51,46). A parabola opens downward and passes through the points (43,45.7), (45,52.4), (47,54.7), (49,52.6), and (51,46.0). All points are approximate.
$D .20602060 x f (x)$
A coordinate system has a horizontal x-axis labeled from 20 to 60 in increments of 2 and a vertical y-axis labeled from 20 to 60 in increments of 2. Data points are plotted at (28,30), (30,36), (32,41), (34,35), and (36,31). A parabola opens downward and passes through the points (28,30.7), (30,37.4), (32,39.7), (34,37.6), and (36,31). All points are approximate.
(C) Use the modeling function f(x) to estimate the mileage for a tire pressure of 29
$ \frac{l b s}{s q} \in .$ and for 35
$ \frac{l b s}{s q} \in .$
The mileage for the tire pressure $29 \frac{l b s}{s q} \in .$ is
The mileage for the tire pressure $35 \frac{l b s}{s q}$ in. is
(Round to two decimal places as needed.)
(D) Write a brief description of the relationship between tire pressure and mileage.
A. As tire pressure increases, mileage decreases to a minimum at a certain tire pressure, then begins to increase.
B. As tire pressure increases, mileage decreases.
C. As tire pressure increases, mileage increases to a maximum at a certain tire pressure, then begins to decrease.
D. As tire pressure increases, mileage increases.

Data Modeling Examples and Frequently Asked Questions