Identify whether each hypothesis is a null (Ho), alternative (Ha), a directional, or a non-directional, one-tailed or two-tailed test. Discuss your answers.

a. Improved working conditions of employees will lead to a greater productivity.

b. The proportion of patients with lung cancer is higher among smokers than among non smokers.

c. A new marketing strategies and approach will not change the number of units sold.

d. There is a difference in the durability and usage of two different brands of cellphones (Oppo vs. Huawei).