After the Opening of a New Store in a City

Multiple Choice

After the opening of a new store in a city district, experts believed that the average price of a number of marketable goods would decrease. To check if this is the case, a researcher collected data from 23 district shops. The researcher conducts a signed-rank sum test and obtains, that the signed-rank statistic is 88. Assuming that the sample is large enough, make a conclusion about the probability of a decrease in the price.

A) The normal approximation of this study gives z = 1.34 and the probability that the price has not decreased is about P = 0.0901.
B) The normal approximation of this study gives z = 1.34 and the probability that the price has not decreased is about P = 0.9099.
C) The normal approximation of this study gives z = 0.05 and the probability that the price has not decreased is about P = 0.4801.
D) The normal approximation of this study gives z = 0.05 and the probability that the price has not decreased is about P = 0.5199.