Answer:
No these these result do not differ at 95% confidence level
Step-by-step explanation:
From the question we are told that
The first concentrations is 
The second concentrations is 
The first sample size is 
The second sample size is 
The first standard deviation is 
The first standard deviation is 
The mean for Turnpike is 
The mean for Tunnel is 
The null hypothesis is 
The alternative hypothesis is 
Generally the test statistics is mathematically represented as



Generally the degree of freedom is mathematically represented as


The significance
is evaluated as

=> 
=> 
The critical value is evaluated as

From the student t- distribution table

So

=> 
given that
we fail to reject the null hypothesis so this mean that the result do not differ