View source: R/simple_hypotheses.R
shypo  R Documentation 
A movie to illustrate statistical concepts involved in the testing
of one simple hypothesis against another. The example used is a
random sample from a normal distribution whose variance is assumed
to be known. The simple hypotheses relate to the value of the mean
\mu
.
shypo(
mu0 = 0,
sd = 6,
eff = sd,
n = 10,
a = mu0 + eff/2,
target_alpha = 0.05,
target_beta = 0.1,
panel_plot = TRUE,
hscale = NA,
vscale = hscale,
delta_n = 1,
delta_a = sd/(10 * sqrt(n)),
delta_eff = sd,
delta_mu0 = 1,
delta_sd = 1
)
mu0 
A numeric scalar. The value of 
sd 
A positive numeric scalar. The (common) standard deviation

eff 
A numeric scalar. The effect size. The amount by which
the value of 
n 
A positive integer scalar. The sample size with which to start the movie. 
a 
A numeric scalar. The critical value of the test with which to
start the movie. H0 is rejected if the sample mean is greater than

target_alpha 
A numeric scalar in (0,1). The target value of the
type I error to be achieved by setting 
target_beta 
A numeric scalar in (0,1). The target value of the
type II error to be achieved by setting 
panel_plot 
A logical parameter that determines whether the plot
is placed inside the panel ( 
hscale , vscale 
Numeric scalars. Scaling parameters for the size
of the plot when 
delta_mu0 , delta_eff , delta_a , delta_n , delta_sd 
Numeric scalars. The
respective amounts by which the values of 
The movie is based on two plots.
The top plot shows the (normal)
probability density functions of the sample mean under the null
hypothesis H0 (mean mu0
) and the alternative hypothesis H1
(mean mu1
, where mu1
> mu0
), with the values
of mu0
and mu1
indicated by vertical dashed lines.
H0 is rejected if the sample mean exceeds the critical value a
,
which is indicated by a vertical black line.
The bottom plot shows how the probabilities of making a type I or type II
error (alpha and beta respectively) depend on the value of a
,
by plotting these probabilities against a
.
A parameter window enables the user to change the values of n
,
a
, mu0
, eff
= mu1
 mu0
or sd
by clicking the +/ buttons.
Radio buttons can be used either to:
set a
to achieve the target type I error probability
target_alpha
, based on the current value of n
;
set a
and (integer) n
to achieve (or better) the
respective target type I and type II error probabilities of
target_alpha
and target_beta
.
If eff = 0
then a plot will be produced even though this case is
not practically meaningful. In the "set a and n to achieve target alpha
and beta" case, the plot will be the same as the case "set a and n by
hand" case.
Nothing is returned, only the animation is produced.
movies
: a userfriendly menu panel.
smovie
: general information about smovie.
# 1. Change a (for fixed n) to achieve alpha = 0.05
# 2. Change a and n to achieve alpha <= 0.05 and beta <= 0.1
shypo(mu0 = 0, eff = 5, n = 16, a = 2.3, delta_a = 0.01)
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