Stats Exam 1

ST 260 Daniel Balena

Type I error

occurs when the sample gives evidence to reject the null hypothesis, but the null hypothesis is actually true (also known as a false positive).

Box and whisper graph

Categorical data

“names” not numbered measurements (countif and vlookup)

Scale data

number, measurements

Discrete

numbers that are “isolated” i.e. shoe size (scale)

Continuous

number data with unlimited options between any two numbers i.e. foot length (scale)

Nominal

names or categories with no implied order (i.e. state, eye color)(categorical)

If the test statistic is "further away" from zero (i.e., the center of the bell-shaped curve) than the critical value, the null hypothesis ______ be rejected.  This means the test statistics is in the "rejection region".

Should

For a hypothesis test, if the p-value is more than the alpha given, the null hypothesis ______ be rejected.

Should not

ordinal

names with an implied order i.e. credit rating category (categorical)

Suppose you calculate the correlation coefficient for a dataset containing the daily gains/losses of Ford's stock price and Starbuck's stock price for the past year. The correlation coefficient is calculated to be a number close to 0. If the price of Ford's stock increased the next day, what would you expect the price of Starbuck's stock to do?

Option A: Increase

Option B: Decrease

Option C: Wouldn't expect one stock price to affect the other

Wouldn't expect one stock price to affect the other

Frequency

the number of times a specific value, observation, or event occurs in a dataset or experiment

mean definition

a measure of central tendency in statistics representing the sum of all values in a dataset divided by the total number of value

Rank

(n+1)/2 n=number of data points

median

The middle value in an ordered dataset, representing the 50th percentile where half the data points are lower and half are higher

Mode

The value in a list of quantitative data that occurs more than any of the other values.

Intersection

only elements that are found in both sets are kept (interchangeable with “and”)

Complement

a set is all the elements (in the sample space) not in the set.

Conditional Probablitity

occurs when additional information shrinks the sample space of the probability assignment

Normal Distribution

For this distribution the mean, median, and mode are always equal to each other, and the mean/median/mode can take on any number from negative infinity to positive infinity.

When does an outlier exist

if a datapoint is larger than the upper limit or lower than the lower limit.

Exponential distribution

For this distribution the mode is always equal to zero, and the mean is always larger than the median.

Uniform distribution

For this distribution there is no mode, and the mean and the median are always equal to each other.

Standard normal distribution

For this distribution the mean, median, and mode are always equal to zero.

range

The distance between the largest and smallest values in a list of quantitative data.

Interquartile range

The distance between the value that is larger than 75% of the values and the value that is larger than 25% of the values in a list of quantitative data.

Standard deviation

The "average" distance each value is from the mean in a list of quantitative data.

Variance

The "average squared" distance each value is from the mean in a list of quantitative data.

Type II error

occurs when the sample gives no evidence to reject the null hypothesis, but the null hypothesis is actually false.