A research group wants to determine whether the proportion of car accidents that were caused by drivers using cell phones has changed from the previous value of 13%. They obtained 10,000 auto accident reports and found that 14% were caused by drivers using cell phones. Find the test statistic.

Answer: -2.88Step-by-step explanation:Hypothesis : The proportion of car accidents that were caused by drivers using cell phones has changed from the previous value =13%i.e. p=0.13Sample size : [tex]10,000[/tex]The proportion of auto accident were caused by drivers using cell phones.[tex]P=0.14[/tex]Now, the test statistic for the population proportion is given by :-[tex]z=\dfrac{p-P}{\sqrt{\dfrac{P(1-P)}{n}}}[/tex][tex]\Rightarrow\ z=\dfrac{0.13-0.14}{\sqrt{\dfrac{0.14(1-0.14)}{10000}}}\Rightarrow\ z=-2.881952088\approx-2.88[/tex]Hence, the value of the test statistic is -2.88