Flashcards in Midterm 1 Deck (52):
which of the following is true about a 95 confidence interval of the mean of a given sample.
There is a 95 chance that the population mean will fall within the limits of the confidence interval.
What does a significance test tell us?
There is an effect in the population of sufficient magnitude to be scientifically interesting.
A type 1 error....
We conclude that there is a meaningful effect in the population when in fact there is not
A null hypothesis is....
Predicts that the experimental treatment will have no effect.
What does a box plot not display?
Which of the following is least affected by outliers....
What does it mean when a researcher rejects a null hypothesis at the .05 level?
There is less than 5% chance of getting such an extreme result by chance if the null hypothesis is true.
The results of the study are not extreme enough to reject the null hypothesis...
None of the above, the results are inconclusive.
Failing to reject the null hypothesis when the research hypothesis is true is referred to as a...
A type 2 error.
In a histogram the vertical dimension shows....
In a distribution of Z scores the mean is always
zero and the standard deviation is always 1
Interval scales of measurment
Have equal distant scales...
example of a ratio scale
Physical distance, there can be a true zero.
The mean is an appropriate measure when....
The data is normally distributed, interval or ratio scale, date in which the mean, median and mode are all equal.
A small sample size
A large population standard deviation
Using a higher significance level ex 99%
You can't be absolute
Confidence level and power
If you increase confidence level, you decrease power because you have to prove more.....
You can use it to see if data is significant but can't say if it's true for certain.
Repetition of experiment
it doesn't matter independent won't increase power.
Large N sample
Sample means will be approximately equal to the population mean.
the more normal the sampling distribution
You need to know the sample size and the population mean to determine the
SD goes up
power goes down
Sampling size goes up
power goes up
The mean of a sample distribution is equal to
population not sample mean.
Consist of a range of values that act as good estimates of the unknown population parameter.
A major factor in determining the length of a confidence interval is the size of the sample.
From a sampling distribution comes from a theoretical population that is normally distributed.
mean, median and mode is the same.
The height of the curve at different values of X
A theorem that tells us how to accumulate information to revise est. of probabilities.
Deals with situations in which each of the independent trials results in one of two mutually exclusive outcomes.
Test for normal distribution
One event will occur given that some other event occurred.
1.5x the interquartile range.
Gave the normal distribution a central role in psychological theory. Especially the theory of mental abilities.
is the population mean.
kernel density plot
Ignore mean and standard deviation.
Problem with histogram
They lose the numerical value of the individual scores.
Stem and Leaf
Most significant digits are the stem, less significant are the leaves. Useful for comparing 2 dif distrubutions
Area under normal distribution equals
Two purposes of inferential statistics
Parameter estimation Hypothesis testing
standard error of mean
is the standard deviation of the distribution of sample means. When it is large, the means are widely scattered The standard error of mean provides a measure of how much distance is expected on average between sample means and
Neyman and Pearso
Type 1 and 2 error
A Type I error
α, is the probability of falsely rejecting the complementary hypothesis when it is true