# Data Capture Practice Problems

## Contents

## Preliminaries

Download the sample data set and load it.

- What variables does the file contain?
- What types of variables are these?
- What fields does
`data`contain? - What data types are these?
- What might each element of data represent?

## Problem 1

At what time did the the fifth trial start?

## Problem 2

What was the average of the payouts vector on the 500th trial?

## Problem 3

Assign to a variable the value of the fourth cell of `ev` in the 400th element of `data`.

## Problem 4

Capture in a vector the reaction times for all trials represented by `data` (field `rt`).

## Problem 5

Capture in a cell array the event times for each trial (field `evt`). There should be one cell for each trial.

## Problem 6

Capture in a matrix (one row for each trial) all payout values for all options in the experiment (field `payouts`). (Hint: `vertcat`.)

## Challenge: Outlier removal

Make a variable containing the reaction times. Make a new vector containing only those reaction times that are within three standard deviations of the mean reaction time.