Aresearcher is interested in whether the color of an animal's surroundings affects learning rate. she tests 16 rats in a box with colorful wallpaper. it is known that the average rat of this strain can learn to run this particular type of maze in a box without any special coloring in 25 trials, with a variance of 64; the distribution is normal. the mean number of trials to learn the maze for the rats tested with the colorful wallpaper is 11. what is the null hypothesis?

The null hypothesis is that the color does not affect the learning rate.

The null hypothesis states that there is no statistical difference between the two items; in this case, between the times in special colored walls or in not-special-colored walls.

Ais the correct answer

Answer: d. 39 cmin the diagram, the approximate length of the minor arc de is 39 centimetres.step-by-step explanation: the formula for the length of an arc in a circle is as displayed below.let the length of the minor arc de = xx = 2( pi )r × angle of sector / 360°from this, we will substitute the values given from the problem into the formula to obtain the length of the minor arc de.x = 2( pi )r × angle of sector / 360°r = radius = 25cmpi as an approximate value = 3.14angle of sector = 120°x = 2( 3.14 )( 25 ) × 120° / 360°x = 157 × 1 / 4x = 39.25x = 39 ( rounded to the nearest whole number as an approximate value )