I am trying to calculate cohen's d (standardised mean difference) for a study that only reports the range (min and max), and not the mean or standard deviation. I am wondering if it's possible to calculate cohen's d using the sample size and range? And if so, what formula will provide the best estimate of d?

Thanks so much,

Dee ]]>

I have some doubts about testing the effect that a decrease in value of x (independent variable) has on y (the dependent variable)

I have two observation point for variable x, so I can calculate the slope or simply the difference in value of x across the two observation points and I regress this difference on y.

I would like to have more information, however, about such a decrease. For instance, if starting with an high value at observation time 1 and decreasing down to a certain level has a stronger effect than the simple decrease?

Any idea on how to operationalize this?

Thank you very much in advance :o

All the Best

Ted ]]>

I am stuck on some stats homework questions! Hoping someone can help me out..

1. A friend flips a coin 10 times and says that the probability of getting a head is 60% because he got six heads. Is the friend referring to an estimated probability or the probability's true value? Explain.

Choose the correct answer below.

A.

This is an estimated probability because it is based on the relative frequency at which an event happens after infinitely many repetitions.

B.

This is the probability's true value because it is based on an experiment.

C.

This is an estimated probability because it is based on an experiment.

D.

This is the probability's true value because it is not based on an experiment.

2. A magician claims that he has a fair coin along dash—"fair" because both sides, heads and tails, are equally likely to land face up when the coin is flipped. SheShe tells you that if you flip the coin six times, the probability of getting six headsheads is StartFraction 1/ 64. Is this an estimated probability or the probability's true value? Explain.

Choose the correct answer below.

A.

This is an estimated probability because it is based on the relative frequency at which an event happens after infinitely many repetitions.

B.

This is the probability's true value because it is based on an experiment.

C.

This is the probability's true value because it is not based on an experiment.

D.

This is an estimated probability because it is based on an experiment.

3. A probability that is based on a short-run relative frequency is called what?

Choose the correct answer below.

A pseudo probability

A practical probability

An estimated probability

The true value of a probability

4. Experiments used to produce estimated probabilities are called what?

Choose the correct answer below.

Frequencies

Theories

Randomizations

Simulations

5. In 2009, it was reported that 19% of households in a certain country owned at least one dog and 21% owned at least one cat. Complete parts a and b below.

a. From this information, is it possible to find the percentage of households that owned at least a cat OR a dog? Why or why not?

A.

It is not possible. The percentage of households that owned at least one cat AND at least one dog must be known, but it is not provided and cannot be determined.

B.

It is possible. The percentage of households that owned at least a cat OR a dog is equal to the sum of the percentage that owned at least one cat and the percentage that owned at least one dog.

C.

It is possible. The percentage of households that owned at least a cat OR a dog is equal to the percentage that owned at least one cat plus the percentage that owned at least one dog minus the product of the percentage that owned at least one cat and the percentage that owned at least one dog.

D.

It is not possible. Unless the percentage of households that owned at least a cat OR a dog is given, it cannot be determined from any other information.

6. Which of the following is the probability that something in the sample space will occur?

Choose the correct answer below.

A.

0.50

B.

0

C.

1

D.

Impossible to determine from the given information

7. Imagine flipping a fair coin many times. Explain what should happen to the proportion of heads as the number of coin flips increases.

Which of the following is the best explanation for what should happen to the proportion of heads as the number of coin flips increases?

A.

The proportion should get closer to 0.5 as the number of flips increases.

B.

The proportion should get closer to 0.75 as the number of flips increases.

C.

The proportion should get closer to 1 as the number of flips increases.

D.

The proportion should get closer to 0 as the number of flips increases. ]]>