A researcher suspects that there is a relationship between an individual’s level of impulsiveness is inversely related to their memory. To test this hypothesis, she administers scale measuring impulsiveness and a free recall test, to a group of 12 volunteers. The impulsiveness scale yields a score ranging from 1 to 10, where higher scores indicate greater amounts of impulsiveness. The free recall test is scored in terms of the number of items correctly recalled from a 20 item list The resulting scores are as follows:
Participant Impulsiveness Score Free Recall
1 9 7
2 10 5
3 8 10
4 3 18
5 5 15
6 7 11
7 8 9
8 6 12
9 1 18
10 2 17
a) Draw a scatter diagram for these data (5 points.)
b) How strong is the relationship between impulsiveness and recall? Calculate the correlation coefficient for these data (15 points.)
c) Interpret the correlation coefficient, What does the value of the correlation coefficient tell us about the relationship between impulsiveness and memory?
2. An imaginative anthropologist has been
measuring the heights of hobbits and has found the following data
:
m = 44 inches s = 6 inches
Assume that the heights of hobbits are normally distributed and answer the following questions below (5 points each):
a) What proportion of the hobbit population taller than 45 inches
b) What proportion of hobbits have heights between 35 and 38 inches?
c) What percentage of the population is shorter than 46 inches?
d) What heights make up the most extreme 7% (both extremely tall and short, but a total of 7% of the population) of the hobbit.population?
e) What heights make up the middle 90% of the hobbit population?
3. Given a distribution with a mean of 50 and a standard deviation of 6, convert the following raw scores to the standard scores indicated: (5 pts.)
a) X=53 to a GRE score
b) X= 36 to an IQ score
4) An urn contains the following distribution of marbles:
Color of marble f
blue 15
green 12
red 13
yellow 17
purple 18
a) What is the probability of selecting a yellow marble at random?
b) What is the probability of selecting a green, a purple or a red marble at
random?
c) What is the probability of selecting, with replacement, 3 marbles, one red, one
yellow and one purple
d) What is the probability of selecting two blue marbles, in a row, with
replacement?
e) What is the probability of selecting two blue marbles in a row without replacement? (10 points)
4. Use the normal curve to answer these questions about the probabilities of heights in the hobbit population, discussed in question 2.
a) What is the probability of randomly selecting a hobbit who is either shorter than 40 inches or taller than 50 inches?
b) What is the probability of randomly selecting two hobbits from the population that are taller than 50 inches?
A researcher suspects that there is a relationship between an individual’s level of impulsiveness is inversely...
4. A jar contains 6 red, 5 green, 4 blue, and 2 yellow marbles. Four marbles are selected without replacement. Determine the probability of the following: DO NOT REDUCE a) One marble of each color is selected. b) The first three marbles are blue and the last marble is yellow. c) All the marbles are blue d) The first two marbles are red and the last two marbles are purple. 5. HORIZON, a national TV provider, reports that today's typical...
The authors of a paper studied the relationship between y = arch height and scores on a number of different motor ability tests for 218 children. They reported the following correlation coefficients. Motor Ability Test Correlation between Test Score and Arch Height Height of Counter Movement Jump -0.03 Hopping: Average Height -0.09 Hopping: Average Power -0.06 Balance, Closed Eyes, One Leg 0.05 Toe Flexion 0.10 (a) Identify the value of the correlation coefficient between average hopping height and arch height....
A company would like to examine the linear relationship between the age and credit score of an individual. The following table shows the credit scores and ages of 5 randomly selected people. These data have a sample correlation coefficient, rounded to three decimal places, of 0.970. Using this data and a = 0.05, test if the population correlation coefficient between a person's age and credit score is different than zero. What conclusions can you draw? Age 39 27 55 26...
3. A researcher was interested in whether there was a relationship between stress and depression scores obtained from emergency health care providers. The data from 10 emergency workers are below. This is the same data you calculated a correlation on in Question 1. We are trying to use stress scores (IV or Predictor) to predict depression scores (DV or outcome). Using SPSS, calculate a linear regression model: Ý a + b X where Y is Depression and X, is stress....
1. A standard six-sided die is rolled. What is the probability of rolling a number greater than 3? Express your answer as a simplified fraction or a decimal rounded to four decimal places. Answer: ____________________ 2. A box contains 48 red marbles, 53 white marbles, and 67 blue marbles. If a marble is randomly selected from the box, what is the probability that it is blue? Express your answer as a simplified fraction or a decimal rounded to four decimal...
1) In a population survey of patients in a rehabilitation hospital, the mean length of stay in the hospital was 12.0 weeks with a standard deviation equal to 1.0 week. The population distribution was normal. a. Out of 100 patients how many would you expect to stay longer than 13 weeks? b. What is the percentile rank of a stay of 11.3 weeks? c. What percentage of patients would you expect to stay between 11.5 weeks and 13.0 weeks? 2)On...
Find the number a Show your work. ssistentes for "cach situation using a list, free diagram or table. " You olla her cute s mes.llow many Many wies are possible? 2. Carmen has a deck of cards wwwbe wutcomes are possible! Wheted10She picks one card and flips a coin. How many 3. Kendall has three jars of poll' balls. O orange and purple golf ball. The third Ball from cach jar Iwany outcomes arep & Oriejar has a white and...
The heights of adult men in a certain country are normally distributed with a mean of 70.4 inches and a standard deviation of 2.5 inches. a. What are the standard score and percentile of a height of 73 inches? The standard score is z = __________ (Round to two decimal places as needed.) The percentile is the ______ percentile. (Round to two decimal places as needed.) b. What are the standard score and percentile of a height of 69 inches?...
A researcher is investigating the relationship between economic development (x) and level of religiosity (y) in ten countries. (The researcher has interval-level measurements for both variables.) The researcher theorizes that citizens of countries at the lower end of the development scale will profess higher levels or religiosity than will citizens of countries at the higher end of the development scale. As development increases, religiosity decreases. Draw and label four sets of axes, like the one below: (E) Suppose the researcher...
Please help with these questions. 5. (12 points) The United States Geological Survey is conducting a study to predict the magnitude of earthquakes based on the depth of the fault below the surface. The magnitudes of several earthquakes (as measured on the Richter scale) were recorded as part of this analysis, and the data is listed below. 7.1 7.7 5.9 6.7 6.9 8.2 2.1 6.8 4.0 6.5 6.7 3.8 5.6 (a) Find the median and quartiles of the data set....