Practice Math Statistics Problems and Master the Concepts

The average zinc concentration recovered from a sample of measurements taken in 36 different locations in a river is found to be 2.6 grams per liter. Find the 95% confidence intervals for the mean zinc concentration in the river. Assume that the population standard deviation is 0.3 gram per liter. $(Z_{0.025} = 1.96, Z_{0.005} = 2.575)$

pancha3 2021-01-10

GIve a correct answer for this question: when we are comparing two population means from two groups (suppose they are called Group 1 and Group 2), which of the following statistics do we use to make a confidence interval or perform a hypothesis test for a difference in means?

SchachtN 2021-01-10

A statistics practitioner took a random sample of 43 observations from a population whose standard deviation is 26 and computed the sample mean to be 108. Note: For each confidence interval, enter your answer in the form (LCL, UCL). You must include the parentheses and the comma between the confidence limits. A. Estimate the population mean with 95% confidence. Confidence Interval = B. Estimate the population mean with 95% confidence, changing the population standard deviation to 58, Confidence Interval = C. Estimate the population mean with 95% confidence, changing the population standard deviation to 8, Confidence Interval =

Caelan 2021-01-10

In 1985, neither Florida nor Georgia had laws banning open alcohol containers in vehicle passenger compartments. By 1990, Florida had passed such a law, but Georgia had not.
(i) Suppose you can collect random samples of the driving-age population in both states, for 1985 and 1990. Let arrest be a binary variable equal to unity if a person was arrested for drunk driving during the year. Without controlling for any other factors, write down a linear probability model that allows you to test whether the open container law reduced the probability of being arrested for drunk driving. Which coefficient in your model measures the effect of the law?
(ii) Why might you want to control for other factors in the model? What might some of these factors be?
(iii) Now, suppose that you can only collect data for 1985 and 1990 at the county level for the two states. The dependent variable would be the fraction of licensed drivers arrested for drunk driving during the year. How does this data structure differ from the individual-level data described in part (i)? What econometric method would you use?

Dottie Parra 2021-01-10

A group of 125 truck owners were asked what brand of truck they owned and whether or not the truck has four-wheel drive. The results are summarized in the two-way table below. Suppose we randomly select one of these truck owners.
$\begin{array}{ccc} Four-wheel drive & No four-wheel drive \\ Ford & 28 & 17 \\ Chevy & 32 & 18 \\ Dodge & 20 & 10 \end{array}$
What is the probability that the person owns a Dodge or has four-wheel drive?
$(a) \frac{20}{80}$
$(b) \frac{20}{125}$
$(c) \frac{80}{125}$
$(d) \frac{90}{125}$
$(e) \frac{110}{125}$

Tyra 2021-01-10

Effect of alcoholic parents A study1 compared personality characteristics between 49 children of alcoholics and a control group of 49 children of nonalcoholics who were matched on age and gender. On a measure of well being, the 49 children of alcoholics had a mean of $26.1 (s = 7.2)$ and the 49 subjects in the control group had a mean of $[28.8 (s = 6.4)]$ . The difference scores between the matched subjects from the two groups had a mean of $2.7 (s = 9.7)$ .
a. Are the groups to be compared independent samples or depentend samples? Why?
b. Show all speps of a test equality of the two population means for a two-sided alternative hypotesis. Report the P-value and interpret.
c. What assumptions must you make the inference in part b to be valid?

mattgondek4 2021-01-10

A population of values has a normal distribution with mean =136.4 and standard deviation =30.2. A random sample of size $n = 158$ is drawn.
Find the probability that a single randomly selected value is greater than 135. Roung your answer to four decimal places.
$P (X > 135) =$ ?

sibuzwaW 2021-01-08

Give a correct answer for this question In order to compare the relationship between two categorical variables, the best inference technique is ?

Khaleesi Herbert 2021-01-08

To find: The confidence interval for the mean population.

amanf 2021-01-08

The table below provides predicted population data about the world and India.
a) What percent of the world population is predicted to live in India in 2035? Round your result to one decimal place.
b) What percent of the world population is predicted to live in India in 2050? Round your result to one decimal place.
c) Calculate the absolute change in the predicted population of India between 2035 and 2050. Round your result to the nearest whole number.

floymdiT 2021-01-08

Chi-square tests are nonparametric tests that examine nominal categories as opposed to numerical values. Consider a situation in which you may want to transform numerical scores into categories. Provide a specific example of a situation in which categories are more informative than the actual values.

preprekomW 2021-01-08

The two-way table below describes the members of the U.S Senate in a recent year.
$\begin{array}{ccc} Male & Female \\ Democrats & 47 & 13 \\ Republicans & 36 & 4 \end{array}$
If we select a U.S. senator at random, what's the probability that the senator is a Democrat?

Nann 2021-01-08

Find all the critical points of the function $f (x) = 5 x^{26} + 12 x^{5} - 60 x^{4} + 56.$ Use the First and/or Second Derivative Test to determine whether each critical point is a local maximum, a local minimum, or neither. You may use either test, or both, but you must show your use of the test(s). You do not need to identify any global extrema.

sodni3 2021-01-07

Find the correlatin coefficient r using bivariate data.

UkusakazaL 2021-01-07

A store sells custom circular rugs. The table shoes the costs c(in dollars) of rugs that have diameter's of d feet. Let the diameter d represent the independent variable. Tell whether the data can be modeled by a linear, an exponential, or quadratic function.

Ava-May Nelson 2021-01-07

Consider the region below $f (x) = (6 - x),$ above the x-axis, and between
$x = 0 a n d x = 6.$
Let $x_{i}$ be the midpoint of the i th subinterval.
Approximate the area of the region using six rectangles. Use the midpoints of each subinterval for the heights of the rectangles. The area is approximately how many square units?

vazelinahS 2021-01-07

The U.S. Census Bureau publishes information on the population of the United States in Current Population Reports. The following table gives the resident U.S. population, in millions of persons, for the years 1990-2009. Forecast the U.S. population in the years 2010 and 2011

$\begin{array}{cc} Year & Population (millions) \\ 1990 & 250 \\ 1991 & 253 \\ 1992 & 257 \\ 1993 & 260 \\ 1994 & 263 \\ 1995 & 266 \\ 1996 & 269 \\ 1997 & 273 \\ 1998 & 276 \\ 1999 & 279 \\ 2000 & 282 \\ 2001 & 285 \\ 2002 & 288 \\ 2003 & 290 \\ 2004 & 293 \\ 2005 & 296 \\ 2006 & 299 \\ 2007 & 302 \\ 2008 & 304 \\ 2009 & 307 \end{array}$

a) Obtain a scatterplot for the data.

b) Find and interpret the regression equation.

c) Mace the specified forecasts.

Khadija Wells 2021-01-07

46 questions regarding the characteristics and interests of subscribers were asked in a Wall Street Journal poll. State whether each of the following questions provides categorical or quantitative data.
a. What age are you?
b. Are you a man or a woman?
c. When did you first start reading the WSJ? High school , college, early career, midcareer, late career, or retirement?
d. How long have you been in your present job or position?
e. What type of vehicle are you considering for you next purchase? Nine response categories include sedan, sports car, SUV, minivan, and so on.

Phoebe 2021-01-06

In $Z_{40} \oplus Z_{30}$ find two subgroups of order 12

nicekikah 2021-01-06

If X and Y are random variables and c is any constant, show that $E (c X) = c E (X)$ .

It’s not surprising that we encounter numerous ""I need help with statistics problems"" requests online because these are met everywhere, not only in economics or engineering. The majority of college statistics problems are also met in Sociology, Journalism, Healthcare, and Political Science. As long as you have statistics problems with solutions and answers, you will find solutions. Take a look at our college statistics math problems to find the answers. These will help college statistics problems be resolved. As you seek help with statistics problems, take your time to explore provided solutions and compare them with your initial instructions.

Improve Your Understanding of College Level Statistics Problems