Develop an effect size measure (round to 2 decimal places) for Chapter 15 question 47 shown below:

Vehicles heading west on Front Street may turn right, turn left, or go straight ahead at Elm Street. The city traffic engineer believes that half of the vehicles will continue straight through the intersection. Of the remaining half, equal proportions will turn right and left. Two hundred vehicles were observed, with the following results. Can we conclude that the traffic engineer is correct? Use the 0.10 significance level.

Frequency: Straight 112, Right Turn 48, Left Turn 40