# tests/testthat/test-paired-test.R In rsquaredacademy/inferr: Inferential Statistics

```context("paired t test")

test_that("output from infer_ts_paired_ttest matches expected output", {

k <- infer_ts_paired_ttest(mtcars, mpg, qsec)
expect_equal(k\$Obs, 32)
expect_equal(round(unname(k\$b[[1]]), 2), c(20.09, 17.85, 2.24))
expect_equal(round(unname(k\$b[[2]]), 2), c(6.03, 1.79, 5.52))
expect_equal(round(unname(k\$b[[3]]), 2), c(1.07, 0.32, 0.98))
expect_equal(unlist(k\$conf_int1), c(17.92, 22.26))
expect_equal(unlist(k\$conf_int2), c(17.2, 18.49))
expect_equal(unlist(k\$conf_int_diff), c(0.25, 4.23))
expect_equal(k\$corr, 0.42)
expect_equal(k\$corsig, 0.02)
expect_equal(unname(k\$tstat), 2.2964)
expect_equal(round(unname(k\$p_lower), 3), 0.986)
expect_equal(round(unname(k\$p_upper), 3), 0.014)
expect_equal(round(unname(k\$p_two_tail), 3), 0.029)
expect_equivalent(k\$var_names, c("mpg", "qsec"))
expect_equivalent(k\$xy, c("mpg - qsec"))
expect_equivalent(k\$alternative, c("both"))
expect_equal(k\$df, 31)
expect_equal(k\$confint, 0.95)
})

test_that("output from paired sample t test is as expected when alternative is less", {
x <- cat("                         Paired Samples Statistics
---------------------------------------------------------------------------
Variables    Obs    Mean     Std. Err.    Std. Dev.    [95% Conf. Interval]
---------------------------------------------------------------------------
read       200    52.23      0.72         10.25         50.8      53.66
write      200    52.77      0.67         9.48         51.45      54.09
---------------------------------------------------------------------------
diff       200    -0.55      0.63         8.89         -1.79       0.69
---------------------------------------------------------------------------

Paired Samples Correlations
-------------------------------------------
Variables      Obs    Correlation    Sig.
read & write    200       0.60        0
-------------------------------------------

Paired Samples Test
-------------------
Ho: mean(read - write) = 0
Ha: mean(read - write) < 0

---------------------------------------
Variables        t       df     Sig.
---------------------------------------
read - write    -0.873    199    0.192
---------------------------------------")

expect_equivalent(print(infer_ts_paired_ttest(
alternative = "less"
)), x)
})

test_that("output from paired sample t test is as expected when alternative is greater", {
x <- cat("                         Paired Samples Statistics
---------------------------------------------------------------------------
Variables    Obs    Mean     Std. Err.    Std. Dev.    [95% Conf. Interval]
---------------------------------------------------------------------------
read       200    52.23      0.72         10.25         50.8      53.66
write      200    52.77      0.67         9.48         51.45      54.09
---------------------------------------------------------------------------
diff       200    -0.55      0.63         8.89         -1.79       0.69
---------------------------------------------------------------------------

Paired Samples Correlations
-------------------------------------------
Variables      Obs    Correlation    Sig.
read & write    200       0.60        0
-------------------------------------------

Paired Samples Test
-------------------
Ho: mean(read - write) = 0
Ha: mean(read - write) > 0

---------------------------------------
Variables        t       df     Sig.
---------------------------------------
read - write    -0.873    199    0.808
---------------------------------------")

expect_equivalent(print(infer_ts_paired_ttest(
alternative = "greater"
)), x)
})

test_that("output from paired sample t test is as expected when alternative is both", {
x <- cat("                         Paired Samples Statistics
---------------------------------------------------------------------------
Variables    Obs    Mean     Std. Err.    Std. Dev.    [95% Conf. Interval]
---------------------------------------------------------------------------
read       200    52.23      0.72         10.25         50.8      53.66
write      200    52.77      0.67         9.48         51.45      54.09
---------------------------------------------------------------------------
diff       200    -0.55      0.63         8.89         -1.79       0.69
---------------------------------------------------------------------------

Paired Samples Correlations
-------------------------------------------
Variables      Obs    Correlation    Sig.
read & write    200       0.60        0
-------------------------------------------

Paired Samples Test
-------------------
Ho: mean(read - write) = 0
Ha: mean(read - write) ~= 0

---------------------------------------
Variables        t       df     Sig.
---------------------------------------
read - write    -0.873    199    0.384
---------------------------------------")

expect_equivalent(print(infer_ts_paired_ttest(
alternative = "both"
)), x)
})

test_that("output from paired sample t test is as expected when alternative is all", {
x <- cat("                         Paired Samples Statistics
---------------------------------------------------------------------------
Variables    Obs    Mean     Std. Err.    Std. Dev.    [95% Conf. Interval]
---------------------------------------------------------------------------
read       200    52.23      0.72         10.25         50.8      53.66
write      200    52.77      0.67         9.48         51.45      54.09
---------------------------------------------------------------------------
diff       200    -0.55      0.63         8.89         -1.79       0.69
---------------------------------------------------------------------------

Paired Samples Correlations
-------------------------------------------
Variables      Obs    Correlation    Sig.
read & write    200       0.60        0
-------------------------------------------

Ho: mean(read - write) = mean(diff) = 0

Ha: mean(diff) < 0      Ha: mean(diff) ~= 0       Ha: mean(diff) > 0
t = -0.873               t = -0.873               t = -0.873
P < t = 0.192           P > |t| = 0.384           P > t = 0.808")

expect_equivalent(print(infer_ts_paired_ttest(