# Chapter 7: Univariate and Descriptive Statistics

Links to a carefully curated collection of Youtube videos provide a host of additional sourcs for you to develop your ability to use R software in an engaging and accessible manner.

Video 7.1: ‘Intro to statistics with R – three measures of central tendency’

Question: What measures of central tendency are discussed in the video?

Video 7.2: ‘Intro to statistics with R – an intro to measures of variability’

Question: What measures of variability are discussed in the video?

Video 7.3: ‘Calculating mean, standard deviation, frequencies in R’

Question 1: How do you look at the mean of a variable in R?

Answer: You use the mean() function.

Question 2: How do you look at the standard deviation of a variable in R?

Answer: You use the sd() function.

Video 7.4: ‘Normal distribution, Z scores, and normal probabilities in R’

Question 1: How do we calculate the probability of a given value of a normally distributed variable in R?

Answer: You use the pnorm() function, where you specify the value, the mean, and the standard deviation of a variable.

Question 2: How do we calculate the probability for a given z-score?

Answer: You use the pnorm() function again, where we specify the z-score value.

Video 7.5: ‘Histograms in R’

Question 1: When is it appropriate to use a histogram for a variable?

Answer: When we want to summarize the distribution of a numeric variable.

Question 2: How do we do a basic histogram in R?

Answer: You use the hist() function.