4 If the point \( (30,50) \) is the point of intersection of the ascending and descending curves, then the sum of its frequency equals \( \begin{array}{llll}\text { (a) } 30 & \text { (b) } 50 & \text { (c) } 60 & \text { (d) } 100\end{array} \)

A significant result is one that has a low probability of occurring by chance (i.e. sampling error). False

Cite as características que um bom diagrama de dispersão deve ter para facilitar a interpretação dos dados.

A statement that the independent variable had no effect is called the alternative hypothesis. True False

For an experiment comparing more than two treatment conditions or more than two groups, you should use analysis of variance (ANOVA), rather than separate \( t \) tests. True False

F-tests and t-tests are usually used to determine whether the experimental groups are significantly different from each other at a certain alpha level. True False