## One Sample T-Test

The Student’s One-sample t-test is used to test the null hypothesis that the true mean is equal to a particular value (typically zero). A low p-value suggests that the null hypothesis is not true, and therefore the true mean must be different from the test value.

The Student’s One-sample t-test assumes that the data are from a normal distribution – in the case that one is unwilling to assume this, the non-parametric Wilcoxon signed-rank can be used in it’s place (However, note that the Wilcoxon signed-rank has a slightly different null hypothesis; that the median is equal to the test value).

### Arguments

 data the data as a data frame vars a vector of strings naming the variables of interest in data students TRUE (default) or FALSE, perform Student's t-tests bf TRUE or FALSE (default), provide Bayes factors bfPrior a number between 0.5 and 2.0 (default 0.707), the prior width to use in calculating Bayes factors wilcoxon TRUE or FALSE (default), perform Wilcoxon signed rank tests testValue a number specifying the value of the null hypothesis hypothesis 'dt' (default), 'gt' or 'lt', the alternative hypothesis; different to testValue, greater than testValue, and less than testValue respectively norm TRUE or FALSE (default), perform Shapiro-wilk tests of normality qq TRUE or FALSE (default), provide a Q-Q plot of residuals meanDiff TRUE or FALSE (default), provide means and standard deviations effectSize TRUE or FALSE (default), provide Cohen's d effect sizes ci TRUE or FALSE (default), provide confidence intervals for the mean difference ciWidth a number between 50 and 99.9 (default: 95), the width of confidence intervals desc TRUE or FALSE (default), provide descriptive statistics plots TRUE or FALSE (default), provide descriptive plots miss 'perAnalysis' or 'listwise', how to handle missing values; 'perAnalysis' excludes missing values for individual dependent variables, 'listwise' excludes a row from all analyses if one of its entries is missing. mann

### Returns

A results object containing:

 results\$ttest a table results\$normality a table results\$descriptives a table results\$plots an image results\$qq an array of images

Tables can be converted to data frames with asDF or as.data.frame(). For example:

results\$ttest\$asDF

as.data.frame(results\$ttest)

Elements in arrays can be accessed with [[n]]. For example:

results\$qq[] # accesses the first element